Even from a practical standpoint, he would never give up a job where he is not expected to do anything, yet still enjoy the best perks of any job in America. There's no community organizer job anywhere that feeds you lobster every night, allows you to play golf on the finest courses for free, always has an open basketball court waiting for you every Sunday at the gym, and provides you with free entertainment in your own house every Wednesday by the biggest celebrities.
Walk away from that? Even Obama isn't that stupid.
This reminds me of Detroit mayor Kwame Kilpatrick. Even as more and more corruption was exposed, he hung on till the end. It was the local paper doing investigations and a text message that brought him down. Along with a legal system willing to do their job.