No, you're right. It's not all on Callahan's head.
It's partially on the players as well. It shows the disparity between Callahan and Chucky. But their former coach, John Gruden was, and still is, a great coach. It's not like he's Jim Fassel, with the country club mentality. He worked hard, and I appreciated that. He built that team that Callahan took to the Superbowl, and then eventually drove into the ground.
You also have to blame the Al Davis, who, other than the decision to move them to LA, has been a visionary. You can't forget free agency too.
Overall, I don't have much faith in Callahan, if you haven't figured that out yet. But then again, what has been done to prove me wrong otherwise???