For all but the ultra wealthy, it absolutely is. Which is my point.
Im decently wealthy, but clearly still working class. As is pretty much everyone else I know around me. Plenty of them have 1 to a few rental properties. I know one guy who just basically covers his costs with rent, and uses them as investments. But all the others use it as a stream of income. So the claim that only the ultra wealthy profit from it makes no sense, and if you think the people you work for are the only ones in the market, then your perspective is terribly inadequate.
My in laws are also sitting on a property that they could rent out for income, and while they are well off, they are not ultra wealthy either.