Or the wrong place at the wrong time depending on how you voted.
I tend to agree with you that Obama's being assigned blame for stuff that's mainly beyond his control and that some of the continuing economic drop is fall-out from policy, government activity, general failure to provide oversight, general willingness to regulate in the wrong way (take your pick) from before he was even in the Senate.
But, I don't think the stimulus bill was all that great and at some point when things don't start rebounding, Obama's going to own this one. (I'm oversimplifying by saying merely "stimulus bill". We could include all the proposed funding and regulation he's had a hand in as well and the strings attached to previous bailout funds that aren't proving popular.)
The fact that it's a Democratically controlled Congress with key long-term Democratic legislators who were players in some of the crisis areas, even when the Republicans were in control, might kind of at least double the pressure. There's no place to shift the blame in the public mind.
(I'm not really saying that I think Democrats are more responsible for the present situation, but at some point, especially considering everything that Bush was blamed for and the pattern that's established, the public is going to look to blame.)