With the GOP's lose of New Mexico and NM's related demographics, Mitt Romney's path to 270 involves winning states that haven't voted for a Republican since 1988.
Bush 2004 + New Hampshire (which voted Republican in 2000 and is probably a tossup at worst for Romney right now)- Iowa - New Mexico - Colorado - Nevada = 270.
So, what kind've person would vote for Mitt Romney after not voting for H.W. 92, Dole, Bush 00, Bush 04 or John McCain?
Well, it would be okay for them to have voted for Bush in 2004 since Romney can generally do worse than that and still win. So, someone who thought the economy was doing bad in 1992, good in 1996, bad in 2000, bad in 2008, and bad in 2012.
Why is Mitt Romney a better candidate than those guys?
He's not, but the alternatives are arguably even worse candidates.