Let's say you own a restaurant. You hire a manager, cooks, servers, a host. But let's say the demand for labor for servers is below a living wage. Your business will fail without the server, but the server cannot survive on a server's salary.
So, you say, it's the fault of the server, for she should be more ambitious. She, too, can be an owner. Okay, sure, you're right. But can all the servers become owners? Obviously not. And even if they could, then business would fail, for who would serve?