Puffy, I certainly don't think it's half. But I think there are several. I think the type of QB is just as important as quality in the Pats situation. QBs that might not be great playmakers, but who don't do a lot of bonehead mistakes would do well for the Pats and I think there's a good chance they'd have won just as much. But it's nothing more than specualtion.
What Brady does well is not make a lot of bonehead plays that allow the other team to score more points. The Pats are a team that jus doesn't give up points (they led the NFL this year by giving up a a paltry 14.9 PPG). Brady's job is to play a conservative offense and not do anything tha will lead to quick points for the other team. I think he does it well, but no matter much I'm told otherwise, I just can't ignore the time he gets to pass. I thought Pittsburgh would be a good test because they had such a good pass rush all season. But I paid very close attention to that part of the Pat-Steelers game and even the Steelers got very little pressure on Brady. He had mass amounts of time to throw the ball most of the game. He never leaves the pocket and usually throws to his third or fourth receiver. That could be because he has the time and he's going to use it. I don't know. I think it would interesting to see him play in a situation that requires him to move around a little and make quicker decisions. I'm not suggesting he couldn't do it, but I'm not convined he could. Honestly, I just don't think we know how good he is by himself yet. He's been in such a favorable environment that it's too hard to tell.
But, it would probably come as no surprise to anyone that I don't put a lot of credence in the "he does it when he needs to" argument. Great QBs are great almost all the time. John Elway didn't just wake up one day late in his career and discover how to "win the super bowl."