And you're now suggesting that instead of renting, property owners should hold the notes on subprime mortgages?

By and large, renters already have subprime credit. Landlords are already taking the risk on renters who would be subprime borrowers. That's how they are making their money: exploiting people who don't have the savings or income to qualify for lending.

Landlords aren't taking on any additional risk by lending to them vs renting to them. They are actually reducing their risk, as the same person as a buyer has more to lose than they would as a renter. Further, a stable mortgage payment becomes more affordable over time, as the borrower's income increases.

and that's assuming the seller doesn't also lose the house at foreclosure, since a foreclosure is a public sale.

That's the stupidest thing you've said. Yes, it's a public sale, and the beneficiary of that sale is the lender. The first bid at a foreclosure sale is always the lender, who bids what they are owed, including the foreclosure costs.

The only way the seller loses the house is if someone over bids them (or they are too stupid to bid the full amount they are owed) But if they are overbid, they receive the proceeds from the sale, and are made whole.

You don't get to talk about damage to the property: landlords have the same risk. The cost and process of a foreclosure is similar to that of an eviction, and the higher interest rate the buyer is paying more than covers it. Further, you're ignoring mortgage insurance that buyers would have to pay for as well.

And the owner-occupier thing? You know people can lie about their residency and building occupancy, right

Sure. That would be tax fraud. Property taxes are public records. Anyone can look up who was claiming what. Including the actual occupant of the property you say you live in, or the neighbor you pissed off. And when they look it up, you're on the hook for all the credits you claimed.

I'd sooner let it sit empty.

That attitude is a problem. You are contributing to the problem. You should be financially discouraged from this problematic course of action.

, it destroys class solidarity thay would otherwise exist between small landowners and renters.

There is no class solidarity between renters and landowners, nor should there be. The relationship of landowner to renter is the same as the relationship between tick and dog, fly and horse, mosquito and human.

Much like "impoverished child" or "battered spouse", "renter" is a class that should not exist, and for much the same reason.

Solidarity between the people you describe is best achieved by converting the renters into landowners.