The two things are fairly tightly connected. If ordinary citizens can't buy house, how does some other citizen (not corporation) buy one and offer it for rent to you?

Yes, absolutely true. I wasn't really saying that not being able to buy a house is a good thing, but I did speak before thinking here.

There are things besides individual citizens and corporations that could, in theory, own and rent housing.

There are a lot of individuals who buy investment properties. I have friends who use this as their primary retirement vehicle and own a bunch of rental properties. They are just successful small-business owners and the properties are their private property, unrelated to the business. From last time I saw statistics on this, most rental units were still owned by small landlords.

Yes quite. But we were contemplating a future where small scale landlords were extinct.

Why would they go extinct though? This makes no sense.