Question is? Does belichek hang it up when Brady hangs it up?
He seems stubborn enough to want to prove he can win without Brady, but Brady is determined to play until age 40 and that would put BB at age 65. You would expect natural rebuilding when Brady retires which might make Belichick want to get out of NE, but the Packers proved you can transition from HOF QB to the next without tanking, so we'll see. Hopefully in two years the Pats can take someone end of the 1st or 2nd round who will be happy to sit on the bench and learn from Brady for 2-3 years before taking over and Belichick will stay on for a few more years with the new QB.
I'm about 100x more of a ND fan than a Pats fan, so this isn't complete bias when I say that I think Belichick is pretty much the best coach of all time and I'd sell my soul for him to coach the next 10 years at ND.
Regardless, I'm in denial that the day of no Brady/Belichick is getting closer.