The Republicans put a lot of effort into convincing the public that Bush's policies no longer have an effect on the economy - even when they do.
So you're probably right that it won't work with voters to point this out - but that doesn't mean that Bush's failed policies aren't still the cause of many of our problems.
I mean, come on. Legislation is legislation. Obama is trying to unwind things like the Bush tax cuts so that we have a lower deficit, but even that is being fought by the Republicans.