Although this video did not help his campaign, Romney had a lot of other problems to deal with. It is always more difficult to beat an incumbent president, and most voters thought Obama was doing a good job. Romney probably did not win because he was a Mormon and many people don't trust this religion.
The matter is Romney actually had many blows to his campaign, the 47 Percent Video was just one of many major blows to his credibility, and amount of votes he gets from his base. Overall Romney was a candidate who did not care very much about the people, and that was what sank his campaign, the 47 Percent video was just a few of the many major blows showing the United States Population this fact.