For the most part Ty was stuck using Bronco's recruits (go hard, go fast crowd), many of whom were ill-suited for Ty's pro-style offense. Detmer made that clear to KS and TH prior to being hired. When KS needed a scapegoat, that fact was conveniently forgotten.
Frankly, I think that Ty would have done better than Grimes with this year's players, assuming KS wouldn't have kept all his buddies around as coaches. A smart & talented QB like ZW would have thrived under Detmer. Everything that I've seen indicates that ZW has a much higher football IQ than Mangum, and without the mental health issues to hold him back.
It still wouldn't have fixed some of the mind-numbing bonehead KS moves that we've seen the past two years though.