He can't win. The system is set up to prevent it. If he looks like taking the nomination, the party apparatus will beyond into gear, and corral the various super delegates into consensus behind the next most popular candidate. And if by some miracle, he made it past the primaries, he'd be crushed in the general.
Does it say something about the American public that he's gown this far? Maybe. But honestly, I'm not so certain that a similar candidate couldn't garner a comparably decent kernel of support among certain sectors of the Australian public that I'm prepared to throws stones. In fact, it's avoiding circuses like this one that have kept me firmly in the monarchist camp in Australia, despite a strong push to moves to a republic from my side of politics. I don't ever want to see an individual liked this expose these sorts of nasty issues in my society.