Why do so many more Americans think Obama will win than want him to win?

It's the media coverage, isn't it?

There’s also a less partisan explanation. That is that people tend to struggle to imagine someone other than the current occupant of the White House as the president until he, well, isn’t anymore — even if they don’t like him or don’t plan to vote for him.

Yes, we do have a way of picturing things continuing as they have been. And no one is really good enough to be President, but the incumbent is already President, so our resistance to picturing a person as President doesn't come into play.