I think it is also possible that he had no true idea of what he was stepping into. Of course he knew who Saban was, knew they have passionate fans, knew they expect championships, etc., but this is his first real exposure to a big time, high pressure football environment as either a coach or a player. Everywhere else he's been, the school wants to win obviously but the football coach is a football coach. Now he's in a "damn, these people are crazy" fish bowl, and I mean that as a compliment. Knoxville is the same way.
It honestly wasn't for all that much more money per year than what Washington was offering, and Washington has a fraction of the pressure. From a pure monetary perspective, in order to compensate him for the added expectations, pressure, etc., Alabama would need to be paying him something like $20-25m/year, which is would obviously be insane. Perhaps he underestimated the pressure; in fact, he probably did, but he had a job that was super cush by comparison and he left it for this. Call me naive, but I think there actually was more than just money in play here.
Hopefully they won't figure out that the "Saban discount" doesn't exist anymore.