Romney always was a weak candidate in terms of his ability to express the benefits of the free market over a command economy. Wishy-Washy from the first he pretty much said whatever was necessary to get the nomination in a field of other weak, or broken, candidates. Herman Cain frightened the Democrats, which is why there was so much attention focused on finding or inventing dirt. In the end he also proved weak.
Romney was perceived as a "moderate" technocrat and was sold as just another rich guy by the Obama campaign. He really did little to dispel these things, with the exception of selecting Paul Ryan as VP, although this is not enough to make a campaign.