Let's not get carried away here. No one in their right mind confuses Peyton Manning with Tom Brady. Put Manning on the Patriots and they probably never lose another game.
Tom Brady is a product of his system. He isn't asked to do too much - just don't lose the game.
Lots of decently good QBs win lots of games due to the team and system they are on. Bradshaw heads up the list. Danny White would be another. As a Dallas fan, I have to put Aikman on that list as well - as soon as the system changed he turned into a very mediocre QB.
You could say that about any QB, even Unitas, or Bart Starr, how did he do after Lombardi left the Packers?
Wow, some people still don't get it ..... Brady completes long passes, short passes, screens, gets rid of the ball before the pressure gets there, makes great decisions. What more do you want from a QB?
On the other hand you have Peyton Manning who ends every year shaking his head and pointing fingers at his teammates after his annual choke routine.