I do not recall the source, but sometime in September, I heard an interview with John McLaughlin, one of the most respected GOP pollsters. He said that Axlerod had been working over all of the polling firms, complaining that the polls were biased against minorities and young voters because they were undersampling women, Latinos, and people with cell phones. In fact, Gallup adjusted their daily tracker at about that same time in response to the complaints (and the lawsuit filed against them by the Justice Department, no doubt).
My theory is that, if Romney wins, the pollsters who predicted otherwise introduced a subtle but pernicious bias into their polls by trying to adjust their samples to fit these demographic factors, and as such, tilted them leftward. In essence, political correctness will have ruined their science, just like "climate change" has done to atmospheric science.