year? No. Too many people make the mistake of applying their situation to someone else's.
It's not disloyal to take another job. Kalani's not on a lifetime contract. He could get fired any given year. His previous contract extension came very late where he was close to not getting the extension at all. BYU/NCAA football could go away...then what? Would head coach at USC help his resume down the road? Build his network? Absolutely.
He has to think about his career too. BYU isn't completely loyal to him so why should he be completely loyal to BYU? There's just no guarantees, especially in his profession.
How many decent head football coaching gigs are there in the world...100? How many anesthesia jobs? 51k in the U.S