lol Your Punk love/obsession knows no boundaries.
While the future is (almost) always uncertain, I think Punk's chances of main eventing Wrestlemania (against Cena at WM27, against Cena/Rock in a triple threat at WM29, against either Orton or Triple H this year at WM30) have already passed him by. They're already building up next year to be Roman Reigns' breakout year, so there's no incentive on WWE's part to call Punk back to get him to headline Mania. Hell, Cena/Bryan II has more chance of headlining Wrestlemania 31 than Cena/Punk does.