Don't think Obama does quite that poorly with W still in the White House and Palin still on the GOP ticket
McCain and Obama were neck and neck in the polls before the Crash with McCain even leading many of them
I think with the debates, Obama would have pulled through enough to win the popular vote by at least 3 or 4. Also, McCain was polling decently well in September but was still doing poorly in the months prior to that. I think the poll bump was the initial approval to Palin being on the ticket and the GOP base rallying around him as their nominee.