Respectfully disagree. Romney’s first loss to McCain came well before Florida. Romney lost New Hampshire to McCain after leading in the polls for a long time and gave McCain an opening.
Mitt Romney is all about slick marketing. The sales pitch runs something like this “Yeah Mittens is a RINO, but he can win in the general because the very same qualities make him radioactive with the conservative base makes Mittens electable in the general”. Oddly I remember the same sales pitch about McCain. That didn’t turn out very well did it?