"The entire offense isn't working"
Yea, that's what happens when you know you only need to commit minimal personnel to defending beyond 5 yards past the line of scrimmage.
The entire premise of run first football is to open up the passing game by drawing the safeties in. The problem is, we can draw in the safeties, and defenses know they could still blitz both CBs and run minimal risk of anything more than a 5 yard gain.
Cassel doesn't make teams pay for blitzing. He doesn't make teams pay for stacking the box. All the guy does is complete passes to the RB and pray for YAC to pad his QB rating. Oh, and he also puts up real pass numbers against horrible defenses and prevents.
Courage is not the absence of fear but rather the judgment that something is more important than fear. The brave may not live forever but the cautious do not live at all.