Probably because John Madden is the reason we even have a football game. When everyone else was putting out ****ty football games Madden was making it good, plus John Madden is like a huge part of the NFL from Coaching,Announcing, Video Games.
With that being said though EA has done a GREAT job on Madden 10 dont get me wrong, but they shouldnt forget their roots and realize competition brings out the best of everyone.