No firing Bo was not a mistake. Bo Pelini was a foul mouthed version of Kirk Ferentz. Win some, lose anything important. How many conference championships? Just relevent enough, but forgetable none the less, other than his temper. Wisconsin might have scored on him again this week. 2009 was his best year and still 4 losses.
Stop living in the past. Literally a decade ago. Bo never brought any trophies home beyond some irrelevant bowl games. Yeah....we were slightly less irrelevant to college football back then when we lost to the Texas Techs and got stomped by running teams setting NCAA records.
Our mistake was hiring Callahan, Pelini, Riley and not firing Frost for cause to save the program millions we could have used to buy linemen. You win in the trenches. If you have the right big bodies on both sides of the line coaching is secondary. DR is great, but a great line makes a 3 star QB/RB look 5*. Him behind a great line and EJ we roll teams.
A Bo isn't needed. No big programs hire our old coaches. Recruiting the lines should be priority one. That will make a coach look smart.