There are pieces all over the Internet talking about why Republicans were so convinced they would win and were so shocked when they did not. The increasingly cocooned nature of the news on the right seems like the culprit to me, and watching Fox News on election night would seem to support that theory.
The whole question though seems particularly crazy when you consider that, if Mitt Romney was representative of the conservative id, that they already knew they had no chance at 47% of the electorate. At that point, Obama needed only to find another 3% of voters to agree with him (plus one, theoretically). The idea that he couldn't go find that is pretty implausible... But if this election taught us anything, I suppose it is that math and conservatism are not good bedfellows.