I wonder what would happen if you'd "outlaw landlords", i.e. everyone has to own the place where you live.
For anyone who doesn't want the hassle of mananging their own property, maintenance would probably shift to dedicated maintenance companies.
Which would probably benefit residents, since you can't switch out a bad landlord without moving, but you can switch out a bad maintenance company without moving.
But it would also give more power to banks, since everyone would have to handle their own financing. This might not be an issue if the lack of landlords causes prices to decline. But for that you would need banks that are properly decentralized, with proper inter-bank competition and lack of political power. Smaller banks take on much more risk with bigger loans, so it drives prices down.
But in the current regime where artificially low interest rates incentivize banks to give out bigger and bigger loans to make the same profit, I doubt anything would materially change if we ban landlords. Since the upward pressure on prices wasn't removed.
As long as the total interest over the life of the loan doesn't change vs low interest rates, high interest rates are much more beneficial to the average person. Since it drives down prices and your loan is paid off in a much shorter amount of time.
This inflationary regime that bankers and corporations cooked up in the last 50 years is what really fucks average people. Unless you change that, I doubt you could have any real change.
You also need to include the investment companies buying property just to hold it and sell when the value is high. This creates artificial scarcity, increasing prices by lowering supply. They aren't renting these properties out, they let them sit empty. I think simply banning corporations from owning houses (and this would obviously need some detailed definition of 'house') you'd immediately see a huge price decline.
There are situations where renting makes a lot more sense, which is why I don't think this would be a good idea. Simply increasing the tax based on number of residential properties owned would help tremendously. Corporations wouldn't be interested in owning residential properties because of the high taxes, and landlords would own at most 3 or 4 properties before the taxes get too high to make any margin.