There is an obvious reason for sub prime lending. The borrowers have bad credit and most (not all) take there debt obligations less seriously than those with good credit. When they default they will damage their already poor credit even further. I suspect most (not all) will walk away without batting an eye. I would not plan on sub prime defaults changing the market as a whole.
The homes the sub prime buyers purchased tend to be in less desireable areas. Knowing what I know about the make up of the Piggington’s, I wouldnt count on buying one of their homes.