No one assumes employment, growth or housing prices to pick up much, if at all — something Obama is essentially powerless to change.
Is the Left really going to argue that Presidents are "powerless" to change the course of the economy? Really? After nearly eighty years of Keynesian intervention as the modus operandi of the Democratic Party?
Besides, there's lots Obama could do to change employment, growth and housing prices. He could repeal Obamacare, he could rein in his regulators, he could make the Bush tax cuts permanent, he could make a serious effort to reform entitlements as a way of cutting the deficit going forward, etc., etc.
He won't do any of this, but that doesn't mean that he's "powerless" to do so.
What he's "powerless" to do is to make false things true... he's "powerless" to make government-run health care, hyper-regulation, higher taxes, and runaway entitlements a successful way to spur a modern economy. Obama's an awfully Orwellian figure -- our most "black is white" and "war is peace" President ever -- but he can't really make black white, or war peace, and he can't make left-wing economics work.
On the other hand, he is "powerless" to affect the economy in at least one respect: he simply lacks the understanding of how the economy works to know what to do.