I think he can still win another one. I'm not sure if he can improve beyond his 2006 size and conditioning combination, but if he can bring something close to that back, he can win it. Once Dennis and Phil improve some more, combined with possible decline in Jay's showings, I doubt he will be able to win. Although Jay still dominates Phil in the rear lat spread. With everyone at their best, at this point I think Jay can still win due to his size advantage. Not for nothing, Jay is huge, and this plays a big role in the judge's eyes, even more than Dennis and his superior structure it seems.
I'm thinking Jay cannot get another Olympia win under his posing suit.
While he did best Ronnie in '06, he was already declining physically. In '07 he showed up and received 2nd, but many people in the audience (pros, gurus, fans...across the board) and message boards said he shouldn't have really gotten top 3, let alone top 6.
His best is behind him, and like Ronnie and everyone else in the sport nowadays, the only thing he can do is get bigger. Again like Ronnie, this is not always the best path to choose.
I'm sure Jay is done with. I wish him the best, but Mr. Olympia he will not be ever again.