I feel like his stay here also has to be looked at from the perspective of career damage control. If he only stayed here 3 or 4 years he'd make his status as a short-timer undeniable and would significantly reduce his market price. At that point he'd have a tough time convincing a top-level program to take a risk on him let alone give him the kind of money that would make it worth his while to leave his current contract here. I'm sure Jimmy Sexton will remind him of this if he ever forgets. After his stop at Miami I think he's at least 10 years away from being able to re-enter the NFL, if ever, so that makes him only downwardly mobile.
In a scenario where he leaves Bama after 4 years his head coaching stops would be 1, 5, 5, 2, and 4 years respectively. The only type of program that would be willing to take him on would be a mid to low level program that was desparate to use him for a few years to pull out of the gutter and those aren't the teams that can afford a $4 million/year coach. I don't see any scenario where he can make anything close to a lateral move in the next 8 years.
Granted there are other coaches out there that seem to move around alot but none has ever taken the shot from the media that Saban has.
I think what probably took him so long to decide on Bama was that he knew in the back of his mind this was going to have to be his last stop. At least for the next 8+ years. Maybe this is one of the topics he discussed with Huizenga.
I'll throw another half-baked thought out there. With all media backlash out there as a result of the hiring, I wouldn't be surprised if the NCAA comes up with some restrictions on coaching contracts/salaries in the near future which could make it more difficult to throw massive amounts of money at coaches to lure them away from their current programs. Just a thought.
Now retirement...