Not that I disagree that Jim is a weirdo, he clearly is. But could this simply be that he likes being at Michigan and he's not going to bolt unless someone literally backs up the Brinks truck and gives him complete control? I mean, if the vibe he's putting out is "I'm not leaving unless you make me an offer I literally can't refuse", and someone makes said offer, he'd take it.
I hardly believe it has to do with money. He's obviously already rich enough to support his regular diet of steak and milk, and Dockers aren't exactly pricey. And Michigan, even with his renegotiation, is still paying him plenty.
At UM he basically gets to be the emperor of the football program. HE makes personnel decisions [players/coaches] and doesn't have to clear his recruiting or roster management with a general manager, as he'd have to do in the NFL with draft selection, trades, salary cap mgmt, etc.
I think he wants complete control more than he cares about $100M.