It should be clear that FHA/Fannie/Freddie DO NOT make housing affordable as they were intended to do, they make housing unaffordable by allowing prices to remain inflated.
The govt CANNOT let housing collapse completely. It is too large a part of the economy. They will drag out the pain for years and hope that the more recent buyers will be a better risk than the previous buyers.
The longer it takes, the more stable the market becomes and they look like they fixed it.
Many established areas will find their own bottom through normal supply and demand, sooner rather than later.
If unemployment gets worse, housing will get MUCH worse.
Housing market is just a cross between a Ponzi scheme and multi level marketing that allows many people to profit, but some people do get burned.