First, TNA cant buy any of the video library you are talking about, that is all owned by Vince McMahon, and in fact has been used in numerous DVD releases including all 3 Flair DVD sets (two solo, one with Horsemen), The Dusty DVD, Best Of Starrcade, Greatest Steel Cage Matches, SuperStars of The 80s, and they just released Greatest WCW PPV Bouts Vol I.
The NWA as it was constructed was a conglomerate of regional promotions, each with their own territory, talent roster, and champions, with one over riding World Champ. Most of what you saw on TV courtesy of their syndicated shows and TBS programs was the small (albeit most popular) niche within the organization specifically controlled by Jim Crockett Jr and his Crockett Promotions. JC was the defacto head of the NWA as much as their was one because the champ (mostly Harley Race & Ric Flair) worked primarily for him and spotlighted his arena shows, TV programming, etc. The NWA champ was obligated to wrestle in all the various territories (they all had their own TV shows and local TV contracts, its amazing how much pro wrestling could air in one week in some TV markets) which at times included Florida Championship Wrestling, Mid South, and World Class (The Von Erich's promotion) among others. It should be noted that when Flair was champ his regular trips to Japan and South America among others, were independent bookings he made on his own, as were his 80s appearances in the AWA, they were not also part of the NWA (and they mostly stopped after 1986 because Crockett wouldn't allow him to wrestle and make money while risking injury for other non NWA promotions).
The majority of fans outside these local areas think only of the NWA as what was shown on TBS, and while that was certainly the biggest part in terms of national success, it wasn't the only part. Fans in some of those local territories may remember seeing Flair for instance in feuds with Jerry Lawler and Ted DiBiase in the mid south, battling a rookie Lex Luger in Florida, etc, none of which was shown on TBS.
As far as the territorial conglomerate goes, Crockett did as much to kill that as Vince McMahon. Went McMahon started breaking out of the established WWE territory and promoting nationwide he would do it slowly, usually buying local TV time for his syndicated programming to air in that market. if it did well, he would run an occasional house show their, usually with a stacked roster star wise. If that did well, he would return for a similar stacked show, maybe buy more TV time, maybe not, and slowly start being a more consistent presence house show wise in the area.
Crockett started doing the same thing, taking the roster he owned as part of Crockett Promotions and running house shows in other territories, some of them NWA territories, and saturating local TV with his syndicated programming to augment that huge advantage he had with his TBS show (WWE had a deal with a national cable channel, WWOR, based in Chicago, but they didn't have the reach TBS did, and the TBS show routinely drew much better ratings in the mid-late 80s than WWE programming on USA on Monday Nights was doing). Crockett started moving up the mid west and into WWE territory as well, enjoying considerable success in Pittsburgh (it was an NWA show from Feb 1987, not any WWE event, that held the attendance record at the old Pittsburgh Civic Arena, a place that hosted multiple Mon Night Raws and PPV events in the 90s), Philadelphia, Cleveland, and further away from the North and back out mid west Chicago and Detroit.
McMahon stayed one step ahead by forcing arenas to sign Exclusivity agreements with him where they could only host his Pro Wrestling shows, which if they violated he could refuse to run shows in their arena. He had a hard time getting these in places like Mid South where his shows did well but he was still behind Crockett Promotions in popularity and acceptance by the fan base (due to their connection to the NWA and the local wrestling companies) and he couldn't get them in die hard NWA/Crockett areas such GA, Tenn, NC, SC, even VA and West VA, because the NWA was more popular, although he was making strides. McMahon did seal off Madison Square Garden, and sealed off the biggest arenas in Philly, CHI, & DET, forcing the NWA to run shows in the secondary arenas, even though they were popular enough in those towns to fill the bigger arenas. It took him several years to get such an agreement in PGH, not until after Crockett was out of the wrestling business and had sold his assets to Ted Turner (the creation of WCW).
So both promoters were invading local territories and by late 1986 both were bidding for the top talent from the now dying local promotions. Fact was the local promotions couldn't compete with slick production values and star power of WWE or the massive exposure of TBS. McMahon had already stocked his roster with stars from rival promotions before he started his expansion (wrestlers went back & forth between territories then, so no one paid much attention at first). When you look at the first 3 WrestleMania events and you see Hulk Hogan (main eventer in AWA), Randy Savage (wrestled for his family owned promotion and appeared in Mid South), Harley Race (Mid South legend & 7 time NWA Champ), Roddy Piper (main eventer NWA), Ricky Steamboat (had been a major star in NWA/Crockett for several years), Greg Valentine (Crockett/NWA), Paul Orndorff (Mid South, plus some Crockett/NWA), Bobby Heenan (AWA), Junkyard Dog (Mid South), you can see a veritable who's who of rival promotions studs mostly signed just before Vince started going national. Now by 86-87 you had a full on bidding war. Promotions in the Mid South area like USWA continued pressing on, mostly without much assistance from Crockett Promotions, while World Class (cut out of the NWA by early 86), AWA (which did try to promote nationally but too late), and Florida all folding or fading fast. Top stars from these areas were switching like Free Agents in baseball (DiBiase to WWE, Rick Rude to JCP, then WWE, Lex Luger to JCP, Curt Henning & The Rockers to WWE, The Fantastics & The Freebirds to JCP, Kerry Von Erich to WWE, Barry Whyndam & Mike Rotunda from WWE to Florida to NWA, Road Warriors to NWA, Ultimate Warrior to WWE, Sting & Dr Death Steve Williams to JCP, Terry Taylor to JCP, then WWE) and numerous other moves. What there wasn't was much movement between the two big companies as they tried to lock up their top stars and keep them from appearing on each others shows, although occasionally a Rick Rude from JCP to WWE or Bam Bam Bigelow from WWE-JCP type move would occur.
So by 1987 both Crockett & McMahon combined are burying the independents and picking apart the pieces to fill out their own rosters, essentially killing the concept of the conglomerate of local promotions in separate territories comprising an all encompassing NWA. In fact, by now Crockett didn't want his talent appearing anywhere but on his shows and TV, making occasional exceptions for stars like Flair to appear in Japan (very lucrative for American wrestlers) but little else, this killing those independents even more as they relied on stars like Flair & Rhodes to appear in their shows against their talent. You can see here how the NWA effectively died, or at least ceased to be anything close to a major entity in wrestling. How did Jim Crockett Promotions fail ?
Crockett made two very costly business decisions. First, JC wanted to up the ante on Vince in terms of running shows nationwide so he expanded their monthly touring significantly, pretty soon NWA shows weren't special events in these towns outside their strong holds, they were expected, and the initial attendance boom turned leveled off. Vince was still careful about his touring business, still focusing most of his live shows in WWE stronghold areas like NY, Mass, CT, etc and only occasionally running live further away in rival areas. This way he maximized profit by staying closer to his his home base playing more to crowds he knew would be big for him, plus this made sure that when he did run events in other territories they would still be "special events" and more likely to draw well. It didn't take long for travel expenses to eat away significantly at the JCP operation. Fact was, with TBS, they easily could have followed the Vince path and made their appearances in other areas "special events" while focusing more of the touring on their primary area, where fact was they were still out drawing WWE. Instead of trying to run monthly shows all over the North East and out west (fighting for territory being vacated by the dying AWA) he still could have run those areas on occasion while solidifying a strong hold in dying territories where he was already connected to the fan base like Florida and St Louis. Crockett didn't do enough to solidify those areas where he was already stronger than Vince, which allowed Vince and WWE to get a competitive foothold there. Vince was already getting Exclusivity Agreements in major cities in his territory to at least slow down Crockett (which he didn't pursue and should have) while Crockett was fighting a two front touring war playing secondary arenas in parts of the North East (less revenue for your travel) and trying to take over the West Coast from the AWA.
Second, Crockett was convinced he needed to buy the assets of the folding UWF. The UWF (Univesral Wrestling Federation) was akin to ECW in the 1980s, loyal, largely niche following, not sustainable nationwide. Crockett started "co promoting" with the UWF in 1987 which wasn't bad, it gave him more time in arenas in the Mid South area where they were based where he was strong to begin with and they did have some significant talent on their roster, including The Freebirds, Steve Williams, and Sting. At the time though Crockett was not financially vested in UWF, they were just sharing arenas and talent. As the company faded into bankruptcy Crockett wanted to lock up as much of their talent as possible so he basically bought the entire operation. This also gave him control of the video library (a goldmine that Vince had been mining alongside the NWA/JCP stuff since he bought he it all from WCW in 2001). It also gave Crockett control of all the local TV contracts the UWF had, some of which were in WWE cities like Pgh & Philly (though Crockett was already successful in those areas). Problem was the UWF owed a lot of money they hadn't paid for that TV time and by buying the company Crockett was now liable for all their debts, IE now he had to pay off the local TV contracts, even ones he didn't necessarily need. Not all the UWF talent was worth keeping also. Crockett lost millions of dollars on this deal, a colossal failure.
Now we compared how the two promoters differed in their approach to live touring and solidifying/expanding their strongholds, lets compare The UWF purchase to WWE's buying out WCW two decades later. In 1987 no one realized the profits in video marketing so you cant blame Crockett for not realizing what he could have done with the video library, plus the UWF (like ECW) was only around for a few years. When Vince bought WCW years later it was clear their was a market for the video library which 13 years later he is still marketing. Talent wise Vince made offers to the talent he wanted, some of whom (Flair, Hogan, Nash, Goldberg) were allowed to wait till their WCW contracts expired or came close before joining. Vince never tried to acquire promotional rights outright for WCW talent, they remained a WCW/Turner Broadcasting entity under the new Time Warner corporate umbrella (by then they owned Turner Broadcasting). Vince also didn't buy the entire company and all it's assets, therefore he couldn't be saddled with any outstanding debt. Vince saw WCW was about to die, he picked off at a nice price what he thought was valuable, made offers to the talent he wanted (and left others twist in the wind) and never got stuck for any WCW related debt. Crockett tried to buy the entire UWF roster (which he quickly had to start pairing down), took on millions in unpaid debt, and ultimately lost his shirt. Fact was, once the UWF folded their TV time would have been vacated and Crockett could have bought what he wanted, in theory so could Vince, but it's unlikely either one could have bought it all and Crockett would have had a leg up in some areas that were more connected to the NWA/JCP. Same with talent, he could have locked up the guys he wanted before the company went under without getting stuck with a bunch of guys he couldn't use.
These two huge mistakes cost Crockett Promotions dearly and ultimately is what lead to the demise of JCP wrestling (what casual fans thought was the NWA airing on TBS and in syndication) and the entrance of Ted Turner directly into the wrestling business, the start of WCW (World Championship Wrestling was the name Crockett used for his own brand of wrestling on TBS under the NWA umbrella, that's where the name came from, they just dropped the NWA name altogether, quit any association with the few remaining independents, and took the name of their TV show).
As far as technology or production they didn't make much difference. Vince, who had a background in arena management, had a better idea conceptually of how to produce colorful TV broadcasts from his time running rock concerts. Vince also promoted a product with a very kid friendly, Disney like atmosphere, less violence, more humor, less serious characters, more fluff characters like Koko B Ware and George Steele, and to go along with much shorter, less athletic, far less brutal matches, usually very boring affairs. The NWA broadcasts under Crockett did have an "old school" feel and look about them but in a sense that fit with their product, a much more adult oriented, violent, show with colorful language (I still remember hearing Ric Flair scream OHH F--- during a televised match with Dusty Rhodes at 11AM on a Sat morning) and to go with the more adult storylines and increased violence and colorful language you had much more physical matches, plus a wider variety of matches with stiff, muscle guys like Road Warriors, technical wrestlers like Whyndam, fast paced tag team bouts, and lots of gimmick matches, Best of 3 Falls, Texas Death, Bullrope and Chain Matches, etc. They would have benefited by slicker production values but in a way that look helped to accentuate the difference in the product. In WWE you had The British Bulldogs trying to get their dog Matilda back, in the NWA people were attacked with baseball bats in parking lots, tied to ropes around their neck and were drug by pick up trucks, women who entered into the fray could be victimized, guys had their faces rubbed in concrete to cut up their entire face, legs were broken, it was a much harsher product. The kind of brutality on display in the NWA would never have been on Vince's 1980s WWE TV, and their more harsh, less flashy look of their programming actually helped I think drive that point home.
So what killed the NWA as a conglomerate of Independent territories promoting with each other ? Jim Crockett Jr & Vince McMahon with their national expansion. What eventually killed the programming under the Jim Crockett Jr umbrella...a handful of costly business mistakes.
