I agree without question that Pelini couldn't get over the hump.But, he has also regularly acknowledged BP couldn't get over the hump. I think Frost understands some of the reasons why BP was let go even if he has respect for him.
Either way, Bo Pelini had failings as a coach and they manifested well before some of the tension between him, Perlman and SE.
All I'm really saying is among Riley, Pelini and Callahan, Pelini did the best job of the three.
The commonality in the past twenty years of Husker football regarding decisions, was Perlman.