It would no doubt be a unique circumstance, but there's plenty of reasons to do it:
1) If Trev felt that the pieces of the team were all performing at a high level and the issue with getting over the top was the culture that the head man set, and there's a guy on staff who you could elevate that would set the standard that is needed, such as Mickey.
2) At a school like Nebraska where a lot of kids came here to play for a position coach, you could obliterate your roster by cleaning house. Honestly, if this staff all leaves after this year, how many of the DBs are still here in 2023? Or Receivers? We're talking mass exodus that can set the roster back 4-5 years.