I can't say I understand what will become of things if those investors go belly up, but I can't say I have any sympathy for investors who've made the housing crisis worse.
Let them crash and put the houses back on the market.
Keep in mind that "investor" doesn't necessarily mean big evil corp.
An "investor" is also someone who saved up enough money for a down payment on a house in their neighborhood that they Airbnb and go over and clean and wash dishes to try to supplement their income.