Than you're giving him credit for.  The point of this process is to select the nominee who will serve the party best in the General Election.  Obama believes he is that man, as do I.  And if he were in a situation where mathematical possibility allowed him to win the nomination I would expect him to stay in it.

such as who may be ahead. It's all about emotional investment in a candidate now. Besides, I read so many people writing about how Obama should drop out because he's a liar, he disenfranchised MI and FL, he's sexist, he's dividing the party, he's racist, etc.

It really seems that our country has become a nation of sore losers....and sore winners. The close margin of so many recent elections has made large numbers of people question their legitimacy. Meanwhile, the other half acts as if it has received a mandate from the people. I'm tired of close elections...