More than one superbowl in a decade, despite being the number one seed so many times?
Either way, he won't leave until Brady retires....he also has nothing more to prove, so I'd guess he'd retire.
I think he'll coach 2 more years after Brady goes. If the LA stadium was complete, I wouldn't put it past him to trade Brady to LA for 2 first round draft picks and let Garopolo take over. He doesn't need Brady to win the div and get to the playoffs. And looking at how Denver just won the whole thing with the worst QB play of possibly ever in a season and playoffs, it may make Bill B take a good look at what he can get for Brady...Why not, like you said, Brady has only given him 1 SB win in a decade. With that shitty div, an average QB can take him deep in the playoffs with a good defense...