That said, I know several people who own multiple homes and lease them out. They often barely break even with mortgage payments, maintenance, dealing with deadbeat tenants, etc. Sure, once a house is paid off, they have a nice source of income, but they're taking a decent amount of risk having so much of their money tied up in such a limited number of investments. Some of them are still under water on rental property mortgages after the 2008 crash.
They're not skimming labour off of their tenants. They're providing a service for a fee.
And if you're talking about large apartment complexes, that's not some landlord "rentier" class. That's a corporation, just like any other.
You don't have to pay to exist; just ask any homeless person. If you want to live in a home or any type of shelter, you have to make it yourself or obtain access to one that has been built. It has always been so. There are various ways to obtain access: squat, pay rent, perform services in exchange, couchsurf, join a commune, convince friends or family to accept you, buy, etc.