It seems highly unlikely that Riley is going to fire his buddies. Callahan didn't, Bo didn't, Frank only did after duress was applied. It's not typical.
And not firing their buddies was the beginning of the end for their careers at Neb.
Callahan's worst defeat, Texas Tech, came five games into his Husker career. Most people, though they loathed the loss and the fashion in which it happened, were willing to give him time to recruit his guys and fully install his scheme. Five games into his career wasn't enough to throw in the towel on the guy - that was the mood of the majority.
I think today, after the Callahan debacle and the Pelini debacle, are just not willing to sit through this again. To an extent you can't blame them, because inept football is hard to watch, and we've been watching it since 2001. We're just not going to see any changes three games into Riley's tenure, or (I'm guessing) even one season into his tenure here. For better, worse or worser, we're stuck with this group for a couple of years, I'm guessing.