I think this is exactly right. He is out of place, over his head, not happy, knows it, most of the world knows it, and everyone would be better off, including Obama.
Then there could be an honest battle for the office by new contenders. We wouldn’t have to vote for a stupid primary victor just because he wasn’t Obama, nor would we risk Obama winning because of an absurd nomination winner.
If the song and dance that got Obama elected was ever more than song and dance, he’s lost that, much as can happen when someone goes from normal (or brilliantly manic) to deeply depressed.