Unless you think that they have been throwing the game up until this point on purpose?
Sometimes a chess master sacrifices pieces early in the game in order to win later in the game.
Most people are not paying as much attention as they did in 2008/2004. Most people are turned off by the whole process, and will only start paying serious attention tonight, and onward. Team Obama wasted a lot of resources in September, but they did not deliver a knockout blow. Each and every time they knocked Mitt onto the mat, he just got back up. You don't win a slug-fest by knocking the other guy down more often than you get knocked down; you win with a knockout, which Romney can still deliver before Election Day.
We heard this argument before the convention. And after the Paul Ryan pick. And after Romney locked down the nomination. "Sure, he's been a mediocre candidate so far, but he's going to astonish you all the more from now on."
This is the point of the analogy I made with Guiliani's 2008 primary campaign on another thread. Giuliani thought that the first four primaries would be a wash, and that if he concentrated his resources on Florida, and won there, he'd come out ahead. The only problem was that he hadn't calculated on the cumulative effect of getting fringe-candidate scores in four primaries in a row.
If you decide to win by losing the first three-quarters of the game, you risk those losses creating a "reality-effect," and leaving you looking like, well, a loser.