Out where I live there are whole neighborhoods built and owned by rental companies. Rows of duplexes, blocks of single family residences built through the 70s and 80s. All rentals for decades, with some houses being sold off variously. And even then many of the buyers in the last 20 odd years were landlords themselves.
The guy I bought my house off of still owned 150 some houses in his direct name in my county, not counting what his business owned or his partners and associates owned directly in their network.
Tenants don't exactly have a whole lot of choices of what they can do on the property, and many can only stay a year or so. It isn't like they invest in the land: so grass.