Yes the Bills could have kept McCoy, no one argues against that. However, it is the job of the GM and staff to evaluate the value based on what the player brings to the table. The 6.5 million is better spent this offseason or possibly extending a current play and it will get used. Whatever happens with this team this year, the decision to move on from McCoy does not move the needle much one way or the other.
What does move the needle is finding a way to beat cover 0, pass protecting better and hitting some deep balls.