There are other reasons to live in a city besides a job. I imagine that as we move toward a "jobless" future cultural and scientific output will increase, and you'll still want to be around the people who are doing the "cool stuff."

But when you're not spending 40+ hours a week working, an hour long journey to do cool stuff isn't as big a deal.

And besides, I think a most of the other people doing cool stuff will want cheaper accommodation as well, and over time particular kinds of cool stuff will congregate in different smaller towns.

But you will have the choice. Also, I imagine that a jobless future will be heavily automated. Cheap autonomous transportation might expand the housing area with sustainable commute. Even more so if you can work remotely part-time and shorter hours.

You'll want to, but you won't be able to afford it. In a future with UBI the city will be for employed people only.