I'd also hazard a guess he really didn't go there for the money, though money is nice. He has a much easier route to a title, better facilities, and a much more rabid fan base, and maybe he likes the challenge of resurrecting a team.
The guy surely doesn't 'need' more money it just helps make decisions easier. I know I would struggle with a decision to move across county to Oregon for a pay raise, but a 50% or whatever pay raise would be hard to turn down.
And yes I have turned down jobs for more money because I like where I'm at but toss enough dollar signs and I would reconsider too.