I don’t know where you are looking up those numbers, but they are just wrong. Romney gained a million votes and won a higher percentage of the total vote.
John McCain: 59,934,814 45.7%
Mitt Romney: 60,932,152 47.2%
http://www.presidency.ucsb.edu/showelection.php?year=2008
I concede that I found numbers which appear to have been incorrect. Romney apparently did receive more popular votes than McLame. Obozo, conversely, received many fewer votes in 2012 than 2008 by a large margin. However, the percentage of eligible registered voters in 2012 was 3.4 percent less than in 2008. I contend that had conservatives not stayed home, or had voted the top of the ticket instead of abstaining, or had not decided to vote for a turd party or write in candidate, the outcome of the 2012 election would have been different. Romney wasn’t a “perfect” candidate. But, he is/was a damned sight better than what is presently occupying the WH.