Of course it's not "unhealthy".
It's ridiculous to suggest it is, to do so makes it sound like he is Ahab chasing his "Moby Dick". If you are in the wrestling business then to be in that final match of Mania is THE pinnacle. It's the moment that he saw his heroes get to and a lot of guys who were NOT as good as him make their own.
Punk is considered by himself, many of his peers and the fans to be in THAT bracket... that deserve that spot once in their careers. As each year passed, you could imagine that frustration boiling...especially seeing Miz and the like getting the spot before you. Miz can say he headlined Mania, Triple H can say he headlined Mania... but Punk can't.
Someone mentioned that Taker only got it 3 times... but he GOT it relatively early on in his career, 7 years in, Punk had about the same time served when he walked, that would play into his mindset. Sure he could accept that someone like Bret or Shawn had to wait about the same time, but then he can point to "useless" lumps like Bundy, flash in the pans like Luger or Yokozuna and guys like Kurt Angle who got it far easier and sooner in their careers than he did. He was good enough to carry the title for a whole year plus...but not to headline Mania?
Of course we know from his interview where he feels the blame lies. For all the "revisionism" Triple H has undergone in recent years, the accusations of him holding guys back has always been there. No one has ever come out and been as explicit as Punk last week. He clearly feels Triple H has prevented him from that spot, either out of jealousy or more likely in his eyes, spite. There may be truth to it, even if it's not as overt as Paul setting out on a campaign to undermine Punk. It doesn't take much for someone with influence to use that for or against someone...but if it's against it's often listened to far more, especially by Vince. Look at how Shawn was able to derail careers and pushes in the 90's like Tatanka and Marty Janetty, telling half truths, lies and just "he's not got the right attitude" to Vince to keep guys from taking "his spot", often unfairly.
There is a saying that if you don't want to be the WWE champion then get out the business. Likewise if you don't want to headline Wrestlemania then why are you bothering? Even a Grado in ICW will dream of it, even if the law of averages is against him ever being that over/signed. But the dream is what motivates and guys like Foley proved ANYONE can headline Mania once...and I really get the impression Punk only wanted it once... and would have been happy forever jobbing/putting others over at Mania after that... but he was denied it and in reality no one could give a valid reason why a Miz deserved it or Yoko was more "over" as a heel or Slaughter gets to have his name as a Mania headliner and he can't. Because there isn't one when the truth is told.
Rock and Cena were "bigger stars" only cos WWE portrayed them to be. There was no reason it couldn't have been Rock v Punk Vs Cena, Dwayne wouldn't have lost anything... arguably Cena would have... so between Cena and Trips... you have a serious "cartel" of self interest beginning to build preventing Punk reaching his goal.
For a guy like Punk who is SO driven that's gonna burn. He summed it up in that interview and it's the one thing that resonated the most with me. He told them if he wasn't good enough, the best they had, fire him... repeatedly. They only did after HE walked out. So that means he was good enough, they just didn't want to give him his dream.
Why would WWE hold him down other than Trips/Cena... because arguably they felt it was their "hold on him", he described "taking them for the team" yet he never said... "I'll do it but I want the Mania final match...guaranteed... this is 3 you owe me and I am calling them ALL in!"
The reality is Punk would have quit either way... as he did or after he got his Mania main event, they knew he'd then be done cos he'd done all he wanted to do... sadly they chose the former way and it ended horribly.