I know a few property-owning/landlord families. They own multiple properties, both residential and commercial. Some of those properties are profitable to rent

I know a few property-owning/landlord families. They own multiple properties, both residential and commercial. Some of those properties are profitable to rent out. Some are not. You rent out the profitable ones. You don't rent out the ones that are not profitable, you just wait until they're worth significantly more than what you paid for them. When they are, you sell them, and you buy more property. Each property leverages the subsequent properties, in terms of both the mortgage credit you have access to, and actual money gained accumulated from rent and sales.