I gotcha dude. What you don't understand is the dynamics of football. Yes, a quarterback is a very important position in situational football, which the nfl is all about. However, there is a distinct difference between Manning and Brady. What you probably don't yet understand (please don't percieve this as a slight, I'm just being honest) is that statistics and gaudy gains are essentially meaningless for player evaluations in football. Manning distributes the ball between three true recievers, mostly working in a gun-first set and sets up a run off of the pass. When the run becomes established, they rely on a bootleg play action off of a zone blocking scheme and run 15 yard drags or posts off of this after sucking up the safeties. Which explains why their passing game is so effective in the third and short type situations and why Dallas Clark is so frequently seen getting behind safeties.
What I am trying to articulate to you is that a dominant defensive player is a far greater asset in situational football.