At what point would AI necessitate UBI? I'm assuming your idea here is, roughly speaking, that at some point, AI will displace a large section of the work force, rendering them homeless and unable to feed themselves, and that to prevent this, UBI would become necessary. But don't we already have homeless folks? Haven't we already been through technological revolutions putting people out on the streets? If this historical precedent is anything to go by, the politically dominant class is perfectly content with people going homeless on account of not being able to find a job. Seems to me that the classical solutions of pumping drugs into the streets, immobilizing the downtrodden, and straight up slavery through the prison system, are much more likely to happen than UBI
Or they make money the way B2B companies do; which seems like companies just shifting money around on the upper layers without it ever really reaching the hands of lower classes.
But the thing is that there's other ways of dealing with discontent in the working class. Sure, UBI is one of them, but there are less pleasant solutions (just do slavery, or have a well paid class of kapos, or sow internal strife by pushing an "it's the Jews/Muslims/trans folks" narrative with the media that you own), and history shows that the politically dominant class is mighty partial to that kind of solution.
EDIT: Maybe I'm too cynical, but as far as I can see the last time serious improvements to the material conditions of the working class were made was when the soviets were still around, and the threat of a worker's revolution still seemed somewhat realistic. I think the politically dominant class has become quite adept at suppressing that kind of thing, and UBI does not seem to be part of their preferred playbook.
