2. I make housing available to 3 other families
This is the point - the second sentence does not actually follow from the first. The person who built the building, either the actual builders or the investors, make it available. At this point, it is a normal service-provision kind of relationship you see across the economy.
Except, with landlords, it isn't that they provide the building. It's that they provide the land. The land is parcelled out in a manner which, at best could be compared to if we just gave rights to parts of the electromagnetic spectrum to whichever radio stations started pumping waves into it first. Of course, in reality, land ownership is usually rooted in much more brutal and sordid stories in America.
So you essentially end up with a class of people who take no risks, provide no service, and add no value, employ nobody, and often literally do nothing.