Don't disagree, but, to be fair, how many points did the Pat's D give up in the 2H of the ATL/NE SB? Certainly NE loses if Brady doesn't produce points, but, as many say, it's a team game.
No denying it's a team game. No denying QB is the most influential position as well in determining the outcome of games. A great QB can make a bad team decent, a decent team good, a good, a good team great and vise versa.
To answer the question, the Pats D gave up 7 points in second half. Of course when a team is up by 19 points at the end of the 3rd quarter that team play's more conservative and is not generally pushing the ball down the field they would otherwise.
And no denying Belichick has turned out to be an exceptional and fortunate HC. Belichick has a good defensive mind, has surrounded himself with an outstanding team of assistant coaches and other assistants, is able to work the draft with the best of them and obviously lives, breaths and sleeps football. However, he was lucky or perhaps blessed to be given the opportunity to build a first rate operation which he has done well. There is a very good chance he does not get that opportunity if Brady isn't, well Brady, after Bledsoe got hurt.
Also Belichick has made some glaring mistakes in crucial situations. Not utilizing timeouts against the Seahawks worked out well given Butler intercepting Wilson's pass to seal the game which btw was identified by one of the Pats longtime research assistants and then practiced how to defend leading up that game in which Butler got picked the first time giving up a TD in practice. But not utilizing timeouts would not have gone over so well had the Seahawks scored on that drive which was highly probable. Then the bizarre benching of Butler in the Eagles Super Bowl win over of the Pats in which the Eagles scored "41" points. I'm thinking Butler could have helped that defense, that day. And putting Gronk with bad knees as the last line of defense in the Miami Miracle game is a mistake a rookie coach should be criticized for.
My main point is that without Brady and a rather large sample size to go on that included having talented QBs in their prime age (Bledsoe, Kosar, Testevarde), Belichick has not shown to be an elite HC if the criteria is based on wins/losses and making the playoffs, let alone making a run in the playoffs. It can't be underestimated how much value Brady has brought besides his ability to read defenses, accuracy, pocket play and being the most clutch QB to ever play the game. Teammates interviewed have referred to his perfectionism in practice and willingness to get on the players to do it right rerunning plays until they do which is basically like having the greatest offensive coach inside of the QB. For a coach to have the best QB all-time buy into, uphold and hold the players he leads to adhere to the system is such a luxury for Belichick that it shouldn't be overlooked.
Even Brady signing a two year contract in 2018 averaging $15,000,000 allowed the Patriots to sign FA not otherwise possible. How many players that would be considered the G.O.A.T. would be willing to be the 21st highest paid player at their position? As much as I like LeBron James I don't see him making that kind of sacrifice choosing max money over quality supporting cast. Hell, even Ryan Tannehill made $4.25 million more dollars than Brady did last year!
To me, Brady has been the most ultimate team player I've ever seen in any sport.