I think the point is you cannot go infinitely far with that concept. Wealth allows you to get a share of the productive capacity of the world. Giving everyone a billion dollars does not automatically mean we have enough production capacity and land to have everyone live in a mansion.

Now we can certainly say that "hey maybe if these guys all didn't have such a big mansion or as many cars everyone else would be better off", but you have to be explicit about that. It's about taking away things people like and to put that effort elsewhere.