Yeah, he isn't just taking the LSU job. He's trying to do maximum damage to Ole Miss on the way out, as "revenge" for not letting him coach the playoffs.

Ole Miss was offering to cash match LSU's offer, so "he got paid more" isn't a valid reason to switch.

There isn't "you can't win at Ole Miss". He has a playoff team this year.

However, the way the college football calendar works for recruiting and transfer portal means LSU needs a new coach NOW. They can't wait until they playoff is over to hire someone. I.e., the new coach will be recruiting people in the January transfer portal.

The funny thing is that, if he doesn't immediately win at LSU, he's going to get fired real quick. Whereas at Ole Miss, after a record-setting season, he probably could have a few mediocre seasons without getting fired.