I really don't think UBI can ever happen in the US. There is a moral imperative of "industriousness". Keynes' prediction (or maybe desire) ~100 years ago of the 15 hour workweek never panned out.

In the US, you're at least as likely to have half the population vote that anyone who cannot find a job should be exterminated, despite a large proportion of those voting for it being the very people most likely to become jobless, because Fox News will convince them it will mostly affect immigrants and/or some other group they're supposed to hate.

How does the moral imperative of industriousness deal with all the skilled jobs being done by the computer?

Keynes prediction more than panned out if you look at the population level.

Instead of everyone working less what happened is less people work. The fact that it took that specific shape is a source of A LOT of problems.