Like they would do to Utah. BYU hires special coaches. Just because Bronco didn't quite get us to where we could be doesn't mean a different coordinator can't.
This whole "has to have HC experience" is ridiculous. You're only citing one example (KW is doing OK, they're still rising, we are falling; meaning, he's figuring things out). I could cite hundreds of coordinator turned successful HCs. Just pick any football team and look at the current HC's resume.
Your logic does not add up.