Why they lost
The New Republic has the answer:
Republicans, on the other hand, pretty much never change. They’re like a Terminator machine (and unlike the governor who played the Terminator and who has dramatically recast his ideology). Crush them in a machine press, or freeze them and blow them into tiny pieces, and they’ll just regroup and keep lurching forward, cutting taxes for the rich and jacking up defense spending.
Ever wonder why that is? It’s because conservatives have an apparatus in place to interpret every election. If Republicans win, it’s because they were conservative. If they lose, it’s because they weren’t. No matter what the facts may be, they will always conclude that the answer is to run further to the right.