Quick attempt to answer the question for BS, as he's obviously so busy that he hasn't had time to log back into his part time job of trolling CU fans.
It's a gamble to wholesale change 90% of the makeup of a team, because so many newcomers could be difficult to pull together and form a sound culture, and avoid the formation of cliques etc.
That of course ignores that the team had poor culture, work ethics and attitudes and had plenty of cliques and players who weren't sure if they were going to buy in.
It ignores that there's no place to go but up.
There's absolutely no historical comparison for doing this this large of a revamp, so gauging it's risk is sort of new ground.
There's absolutely no historical comparison for a coach who pulls people together like Coach Prime. A great motivator of men.
TLDR version:
Rhule couldn't pull it off, period. Frost and Pelini were the opposite personalities, good at putting people off.
Only a few CFB head coaches probably could attempt it. Prime is one of them. Bill McCartney was one of the others.
Magic Johnson could do this perhaps. Nick Saban could do it and if he left Alabama, he'd do it in a heartbeat.
This is not happening in Lincoln Nebraska ever. So why not rip it?