Why the investment funds have to build the houses? Houses has been built/funded from zero by the future owners since forever, either individually or through cooperatives. That way, "investors" don't need a positive ROI, and they happily lose money overall if they get a home.

I know some people that are currently "willing to invest" in buying a ship container or two and transform it into a house to get costs down. The problem? Regulations don't allow them to put the container in their own property.

The invisible hand is zoning. There's plenty of investment available but you literally aren't allowed to build what would be useful in most cases.

Sure you're free to go out into the middle of nowhere and build all sorts of wild stuff but there's no market for that because that isn't actually what anyone wants. You can't blame the investors when what people actually want to pay for has effectively been outlawed.