I don't blame the Steelers' poor performance on Cowher either. But a young Cowher, with his head and heart fully into the game, would been chewing on asses left and right in the face of the poor playing and dump penalties. Instead, he just shrugged it off.
I don't think that makes him a quitter, just not the "young Cowher" he used to be. Few of us are. Maybe he was a tad bit too satisfied early in the year, I can grant you that.
The Steelers were in the top 10 in offense and defense (for most of the season at least). The dumb penalites and turnovers killed this season, not otherwise poor play. Both these can be corrected by coaching to a great extent. Moreover, he made stupid coaching decisions this year, and even worse personnel decisions (e.g. cutting Chidi and keeping Morey and Staley, starting Ben in the Oakland game when he appeared concussed).