That line of reasoning is faulty and ignores fundamental changes that have altered the political landscape in 4 years - a hugely unpopular Bush (fav. rating half of what it was in 2004), unprecedented stock market collapse in 3 weeks, massive pro-Obama MSM bias, massive money advantage for Obama, enthusiastic Dem electorate, and signs of a recession. It would be a miracle if this did not have an effect.
Of course, you could be right. Maybe. Possibly. ;') Vote anyway.