As for the bigger issue (and ignoring the hypothesis/theory) discussion, I have to say I've heard from a few sources who teach at Cal that Alamar was a done deal after the Bowl Game. As for Gregory, I think JT made it clear things needed to change, Gregory didn't want to change, so Gregory left. Describing it as his decision, being pushed out, whatever, is really not all that important to me. Gregory is gone, and it wasn't by accident (and probably not by firing squad) nor entirely his "choice."
I think the outcome, the conclusion, of having two "friends" leaves means JT has heard the message. And I think that coaches typically get fired for three reasons: bad record (I don't think that is the case here), sanctions (nope) or a perception that the coach cannot change and they've hit their peak. JT's current status is he's now got two new coaches in the two areas most needing improvement. That shows change. Buys him a few years, assuming we don't tank.