I big reason for why teams miss on players has to do with heart. Some of these guys that get drafted see it as winning the lotto. They may not even really like playing football, but they can. And they get some coin in their pocket and the desire to keep doing it is gone. That and the mental makeup of a player. Can he handle the rigors of then NFL.
As much as the arm chair GMs like to think they can evaluate talent, the guys that do it for a living have access to far more information. They talk to college coaches. They get an understanding of what was being asked of a player on certain plays. They know how they practice. They have access to the game video.
And yes, bottom line, they still miss on guys.
