Romney just seemed to have a bad approach to the situation. His tone and approach seemed more to demonize the 47% he was referring to than to the tax system that caused their situation to begin with.
On some level I think that the demonization is "fair" given the number of people who are able to successfully game the system, I know the libs will spout off about how it is truly a fraction of the overal "taker" population, but perception is reality, and I can't think of one person that I know who doesn't know of a few situations were they see people abusing welfare or the free ride machine.
What to me is sad is that the majority of the US seemingly is "ok" with that on some level given the last election, or they have a problem with someone calling it like it is which is why we see such an abundance of 'he is so hurtful' or 'he is so wrong" blah blah responses.
In short, do I think the quote cost Romney votes, absolutely
do I think it cost him the election, not in one bit
The liberal Robin Hood/blame Bush/Occupy movement was in fully effect and the shitty economy combined with the big bailouts for the banks and the perks those execs were getting from abuse of that had people motivated to want more stuff from the government.
Plus Romney was running the whitest ticket in the universe (well could have been worse if his running made was an old dude), so he was destined to fail.