Demographics are what they are. Traditionalist republican strong holds like Christian voters where up from 2008 but down from 2006. Obama strong holds like African Americans and Hispanic voters where down from 2008 but up from 2006. Its about getting the vote out. This was so close in key states like CO, CL, and OH that if Republicans got more of the vote out this easily could have gone the other way.
If you think this election was not about getting the vote out your lying to your self.