the country he should definitely take it. If he loses to South Florida tomorrow and loses 5 more game this year he's on the hot seat. Extension or not, there are no guarantees for coaches not named Saban, Dabo, Smart, and a few others (and even they have only bought themselves 2 or 3 bad seasons). His whole livelihood depends on 18 year olds making good decisions, following direction, and staying healthy. It wasn't long ago that CougarNation was calling for his head (go look up the 2017 schedule).
USC provides so much more for a coach than money. It's a cheat code for a coach. Instantly he gets better recruits, more money, a cushier life. Besides all the unique stuff at BYU he no longer has to worry about, he gets to walk into a top recruits house and be a favorite to land him. He gets to be more selective on those 18 year olds he's so dependent on. It's one of the most sought after jobs in the country, while the BYU job.....isn't.
Just like with Bronco, if Kalani takes another job to try and maximize his worth and provide further long term stability for his family I will wish him well and root for him in every game he plays that isn't vs BYU.