His camp was right, the pollster had is wrong as far as the base of voters. They just stumbled into the right results on election day because some many Republicans did not show up to vote.
Romney did a good job of explaining the difference between he and Obama. What he did not do well is explain how implementing his ideas would make a difference. Thus undecided voted for the safe incumbent and people stayed home.
Did you pay attention? Every speech was about how his ideas would create 12 million new jobs in his first term. How it would raise personal incomes that have eroded under Obama. How we'd be more secure financially. So your point is flat wrong.
People voted for the 'safe incumbent' because Obama ran against Bush for 4 years so tying Romney's proposals to Bush's policies, however ridiculous, scared off already weary and afraid voters from making a change. Exit polls showed people blame Bush for the economy more than Obama. That's not on Romney.
Add in the "historical nature" of Obama's presidency and Obama won by begging for more time and instilling fear of the unknown.