I can't believe this thread has this many pages.
I thought it was clear that only one thing could make Saban leave Alabama and that was if expectations were too high. In other words, if we don't get all nutty and throw bricks through his window because Alabama doesn't win a national championship, things should be ok in that regard. If we support the team well, and manage expectations, he won't have any reason to leave.
He's built a true legacy at Alabama and he's making history. If he left for another job it would do great harm to his legacy. Also, the simple fact is that he can have a greater impact in college than at the NFL level. Although we hate to think about it, if Nick Saban had to do it over again he probably would have stayed at LSU. He not only "lost", 2005 and 2006, but clearly 2007 at Alabama was a rebuilding year. As I see it, he's making up for lost time. He might enjoy building up a program, but he is 61. Imagine if he went some other place in college and had to compete with two of his creations in Alabama and LSU. He might simply run out of time before he got things on track.
And, the NFL? He left for less money the first time. What's in it for him besides a big wad of cash? He's a great coach, but they have a cap in the NFL, he can't retool a lineup like he can in college. Every move that Nick Saban made, made sense. Each move in college was a step up, and the move to the NFL was seen as a step up. But, Nick Saban realized that what he was best suited for was college and he returned. There's no other step up for Nick Saban, now it's a matter of building on his legacy.