Running QBs in the NFL have a limited life span and limited ability.
Vick had QB ratings of:
2004 78.1
2003 69
2002 81.6 (his best year, still one of the worst in the league)
2001 62.7
His overall rating is 76.9.
These ratings are, in a word, terrible. This is also proof he is a running back that passes the ball. Kordell Stewart all over again, Old Kordell was in the league as a QB for 5 years or so and they kept trying to stick with him, before realizing the NFL isn't the place for Wishbone-T QBs.
I don't put much stock in these "ratings"