I seriously think that he is at the company because he likes his job. He probably identifies strongly at the company and feels that it is his responsibility to stay with the company.
it is a joke to think that $1/year salary has anything to do with Job's remuneration which takes place largely in Apple's stock. The better Apple does, the better he does. He's got incentive, regardless of whatever ersatz salary he nominally receives.
So, yeah, i think he's doing it cause he's a control freak who gets high off of being in charge of one of the most important tech consumer companies in the world. But to claim that he's not benefitting massively off of Apple's continued financial success is definitely not true.
That's the understatement of the century. Apple is not a company, it's a exoskeleton for Steve Jobs. The two entirely symbiotic and probably cannot survive on their own anymore.
And when something doesn't come out right, he can breath a little fire (e.g. MobileMe problems a year back or so)