With regards to Guenther, I remember attending an alumni affair where Guenther spoke to the blue hairs in West Palm (before I was a blue hair) and his comment was Michigan and Illinois were in similar places back when Michigan hired Bo, both had some history, but some recent troubles, Michigan stuck with Bo, while Illinois dumped the coach & began/continued some dark days/years. From this it was obvious his philosophy was you needed to give the coach an adequate chance to succeed and he wasn't a big fan of rolling the dice and starting over.
That is true, in the mid 60s Illinois was in pretty good position as a Big Ten football program. The Slush Fund scandal had a lot to do with the subsequent coaching instability as much as "sticking with" anyone. Just terrible timing for us, really killed the program right as TV was starting to discover college sports.