Certainly that's a difficult question to answer with confidence because things can change so abruptly and completely in the world of professional wrestling. Guys get pushed or de-pushed at the drop of a hat. Injuries happen, guys jump ship, so many things can change over the course of a career.
If I were to pick a final number or major world titles that Swagger will hold by the time he hangs the boots up, my guess would be: ONE.
I don't consider the ECW Championship to be a bonafide world title. The only ones that I would classify as world titles would be the WWE championship, the World Heavyweight championship, and a Unified championship, if this returns as has been speculated recently. Therefore, I don't count Swagger's ECW title here, and the only one I count is his brief and uneventful recent run as WHC on Smackdown. I wouldn't be shocked if he never held a major championship again.
As I see it, he's well down the list in terms of pecking order. If they consolidate the two current major titles into one Unified title as I've been reading about on here, he falls even further down the list. There are just too many guys who are better, who have better in-ring work, better mic skills, better connections with the crowds (positive or negative), and I personally find Swagger too bland and generic to jump himself up the list. I know he's young and likely has a long career ahead of him, with lots of time to tweak his character, but it just seems to me that his recent run fell short of expectations, fell flat, and he won't be given another opportunity any time soon.
Fairly or otherwise, his speech impediment will hold him back too. He's very distracting to listen to on the mic, and to be an effective champion, especially a heel champion, you have to be able to handle yourself on the mic. Case in point, see the Awesome one on RAW.
Chance are I'm wrong and he'll get another shot at some point. But that's hardly a certainty at this point and I definitely wouldn't be shocked if he did not.