The economy is Obama's responsibility, I have not written otherwise.
Presidents take credit for economic expansion and are held responsible for economic failure but for the most part, president's have little impact on the economy. They can use the office of the president to throw their support behind legislation and veto legislation but that's about it. The president submits a budget to congress, but it is congress that controls the spending not the president. The discretionary spending is only 1% of the budget.
The greatest impact on the economy is the private sector, followed by the federal reserve and congress. Yet we always hold the president responsible for the economy. I guess that's not surprising since we hold the president responsible for rising gas prices, scandals in government, failures in our educational system, illegal immigration, swine flu, and the war 1812.
If we held presidents responsible for the administration of the executive branch, which is their real job, then we just might get better results.