Well, I guess the argument would be that a billionaire financing the construction of space habitats could make them effectively company towns, but of a highly educated workforce. Once enough of them are there they'll have their own economy, and whoever owns them/the oxygen supply/whatever would be getting a lot of return. I don't think that's a great argument, though, for multiple reasons. I think it's better to just frame it as building a legacy. Put humans in an entirely new place that many of us desperately want to be, end up having the equivalent of a city named after you.