Not sure what you think that poll means. Aside from having a MoE of about 99 points, it has no meaning at all. For example, I voted "no" because I don't "plan" on any candidate this far out, especially without knowing who all of the candidates will be. That certainly doesn't mean I'm not going to vote for him.
And if you think the current economy (as of today) is any indication, then you must be blocking out the economy at this point in Ronald Reagan's first term. Unemployment was higher (increasing 39% compared to a 15% increase under Obama). The debt increased almost as much under Reagan (29%) as it has under Obama (32%). And Reagan went on to an easy re-election.
As someone else pointed out, if the unemployment rate continues to drop, Obama is going to be tough to beat.