Just trying to figure out if you're saying it's mostly the QB and not the coaching. Brady could also have four less Super Bowls if not for an ineptly coached Falcons team that wanted to try to embarrass the Pats, the worst play call in goal line Superbowl history and the best clutch kicker in history.
I do think Brady is the GOAT, not trying to diminish that.
I think to have the success they've had, it has to be a combination of both. This is Brady's 18th season as the starter for a majority of the season (removing 2007 when he played one game). In those 17 seasons, they've won 12 games 12 times, they've been to 13 AFC Championship games, 9 Super Bowls, and won 6. That doesn't just happen with a GOAT QB or GOAT Coach on their own. There are seasons where it has more to do with Brady and season where it's more about Belichick.
You see people (not here) talk about how bad of a stat QB wins is, but when you've got an almost 20 year dynasty, and the only constants are Belichick and Brady, that has got to mean something.
As a side note, addressing
@Therick67 's post above, one of my favorite Brady stats is that he has better numbers both in a dome and outdoors, respectively, than Brees and Manning. Brady has played just 5% of his games in a dome, while Manning is at 35% and Brees is at 49%. That doesn't even consider that Brady has played in worse weather too, considering their respective divisions.