McNabb has been a good QB for Philly but he hasn't won when it counted. We all know Kolb is the future, why not get rid of the past?!!! 
There have been many QBs who look good when they have to come in for a short burst, but when they're made the #1 QB on the depth chart they fall apart.
Just look at the recently released Derek Anderson. He went from a Pro-Bowler to one of the worst starting QBs in the league. It's easier to go out and perform when you know you're just a backup and you're not expected to carry your team.
IF a QB is to be traded, I agree with you, it should be McNabb. I also agree that, for better or worse, Kolb is the future of the Eagles. He had a few 300+ yard games when McNabb was out this past season and looked more than capable.
But this team is still very good. Why risk getting rid of McNabb?
First, there's this. ^^^^
Second, there's the fact that perhaps you don't want the game riding on McNabb's arm. Perhaps, they should think about using McCoy's legs. *kanyeshrug*
Then, there's the Matt Cassel factor. He played in Brady's stead, but he didn't look like much in KC this past season. Who's to say that won't happen to Kolb.
We're speculating right now. Maybe, the move to Kolb will work for the Eagles the way the move to Young worked for the Niners back in the 90s. As a Cowboys fan, I pray that's NOT the case.
