I can't see that being a realistic outcome. We're a long, long way from that, if it is possible. Billionaires are only billionaires because people buy their company shares. If no-one has any money and we're consigned to scrape in the dust for food, what will billionaires do? Who will buy their products, their shares?
Somehow there is always this huge leap between "Strong AI" -> stuff happens -> "about 10k people live in cloud cities and everyone else lives in the dirt".
Money is a tool that has no value by itself. Billionaires are billionaires because they get a much bigger part of the work their group is producing (the group can be one company, a region, a country or the whole world depending on how you see things). If AI does the work instead of people, it will change nothing for them.
You can be optimistic (it will self regulate and everyone will benefit from AI) or pessimistic (only the billionaire class will benefit from AI). But in any case, there will be no need to sell products or share if there is a class of artificial slaves that can replace workers
Somehow there is always this huge leap between "Strong AI" -> stuff happens -> "about 10k people live in cloud cities and everyone else lives in the dirt".
I find it completely implausible.