Even if the government manipulates the interest rates to keep it low, it may not last forever. One has to bear in mind that the government has already been in debt or has been overspending to help the economy recover. The budget used to implement such activity is almost consumed. But one of the reasons is economy. It has been crawling slowly to recovery. And even if there is no assurance that it will stabilize any time soon, the interest rates can change because of other factors.