A free society will by definition be unequal; people have different priorities and abilities, and wealth acquisition isn't a zero sum game. If anything, instead of vilifying billionaires, take a look at the unelected but taxpayer funded and vastly bloated bureaucracies in every country around the world. The shocking revelations of USAID spending billions upon billions to interfere in other countries is example enough.
Prisons are the most equal places in the world in terms of living standards and options available to prisoners; nobody sees them as ideal.
Now lack of upward class mobility - that's a separate problem area to focus on.