I wouldn't be so sure - wherever he would leave for is going to pay him, and pay him very very well. I also wouldn't underestimate his desire to "stick it to Kentucky" by leaving (if it's for a different college team) and beating Kentucky, on the court and with recruiting. I'm sure he'd loooooooove to show a certain segment of BBN what's what
Could a poor March and a fanbase/booster revolt drive him to the NBA? Very possible, but I have my doubts with how many NBA teams want to hire a failed, short-stint former pro coach at Cal's age. No shortage of professional coaches looking for jobs/promotions.