Presumably if we're all unemployed or employed in jobs that have zero economic worth to them, they'll buy all of our houses, build a bunch of big grey boxes for us to live in like a human zoo, build even bigger and more tasteless McMansions for themselves, and pass legislation that makes it illegal to live near them or inconvenience them.
The quality of life for the bottom 90% of the world has been getting better because they were so desperately poor that they could rely on economic growth to help them. At some point they're going to be rich enough in commodities that they start looking to buy things like houses or start businesses, at which point they'll find that asset prices are rising faster than their own wealth because of growing inequality, and they will look at their big grey boxes full of shoebox apartments and start to become unhappy too.