I think Brady will play until he's 45, like he's said many times.
But would it surprise me if he did end up retiring after this season if they win the Super Bowl? Honestly, not really. By then, he'll have 7 rings (more than ANY single franchise in history - including the Steelers who as a franchise has 6). Most rings of anyone besides basically Bill Russell. Most in the NFL I believe.
Again, I still think he'll play for 2-3 more years with New England and that these recent reports are mostly just fluff. It just wouldn't surprise me if he did retire after another SB win, as that would be him leaving on a high, and probably historic note not just in football, but all of sports.
What would surprise me though, is if Brady is playing on another team after this season. I mean, that would shock me a ton. I think he'll either play for 2-3 more years here, or retire after this season. I don't think there's an "in-between" (barring some major injury which ultimately ends his career), and I highly doubt he plays elsewhere.