Rates are not changed randomly or on a whim. Ideally, they are used to regulated the economy, made higher when the economy is going to fast, lower when it needs a boost. Unfortunately, it was kept low during during a 'go fast' period (like running a car at 8000RPM going down hill) and the economy expanded to far, burning itself out. Rates are now so low, making them much lower would be the equivalent of paying someone to borrow your money. Add to that our severe contraction, and there is little reason to change the rate much in either direction.
Short answer, it will be some time before the economy is racing along again at a pace that we would want to raise rates, slowing it down.
And keep in mind, house prices are not that low. Just lower than the inflated (burn out) prices of 05.