Romney was winning, until Obama coined the term "Romneysia"; that was the turning point, after that the momentum shifted back to Obama.
Of course every primary voter had ample evidence Romney was a serial flip-flopper, not to mention his ties to many failed companies which made easy fodder for ads accusing him of layoffs, hurting the middle class, the same ads Kennedy killed him with in 1994.
Nevertheless the voters nominated him because Coulter, Drudge, Medved, Prager, Bennett, Krauthammer, etc. all pushed him, often backing him up on his assertion that he was a "severe conservative," just what we needed. Now that he lost, some of these same people are calling for the party to become moderate, despite Romney agreeing with Obama half the time in the debates.