So far as I can tell, the capacity to do that is called "communism". Specifically "fully automated luxury communism". Why? Because governments are the only entities capable of making such a robust guarantee, and they can only do it without hyperinflation if they own the means of production… which in this case would be the AI.

Now, convincing a government to take an AI into public ownership and use its economic productivity to fund a UBI, that's going to be hard work, and will need evidence to show which of the many options within this very ill-defined and barely researched topic will work vs. which are mere wishful thinking.

This research is what's currently being funded by the actual entity you're most visibly upset with (OpenAI).

And that research may well also determine the answer is "no", at which point we have to come up with something else.

Saying "if you want that why don't you fund it yourself?" was a retort against government funded pensions back in the Victorian era, which I mention because pensions are an age-gated UBI[0]. It's never sufficient to find volunteers for stuff of this scale in a democracy, because "sufficient" is on the same scale as becoming the government and changing the laws.

[0] thus not literally universal, but that's always going to be a sticking point — one open question is if "UBI" should apply to just "all adults" or be the same rate also for minors