I've been saying this whole election cycle that the GOP is making a mistake by satisfying the far right versus crafting a more moderate platform. I'm not sure exactly how or why that element has taken control of the party, but they have, and so I think where they are was somewhat inevitable. I mean if you look at the other potentials, Romney was one of the most moderate.
Partly, I think the problem is that Romney has been trying to be (or forced to be) more ideological than he actually is. As Governor, he was considered to be fairly moderate. Perhaps part of his problems is that he is speaking a message that isn't really his. That is tough for anyone.
Some of the core elements of the GOP resonate with a lot of people. Strong pro-traditional families, creating favorable economic environments, constitutionalism, efficient and limited government, etc. They could do well, just sicking to these, but instead have chosen to shave off all the edges, with draconian immigration policies, moochers vs. takers rhetoric, legislating uteruses, reworking Medicare, etc. It is almost like they have intentionally tried to drive away every group other than older white males. I don't get it. Romney, however, was the better option for a moderate platform, so I don't think a do-over would help them much.
Part of me really suspects that the far right is simply freaking out in the face of demographic inevitability and this is essentially their last stand.