The problem is that in American home-buying, insurance is often compulsory for a purchase with a mortgage. This makes sense from the bank's perspective--they want to insure their collateral. However, the system doesn't really have an answer for "what happens when their collateral becomes uninsurable?" Even though lenders have force-placed insurance, even those insurers can deny coverage in certain circumstances (e.g.…
Would you want to hold collateral that has a high risk of becoming worthless? You would effectively be self insuring it and would have to price that into a loan you offered.