To extend the already really tortured analogy, we've got people who've managed to hoard many billions of... willing blowjob givers? And we've got people who... die from lack of blowjobs.
I mean, even if you take all the billionaires money and somehow liquidate it in efficient way it will only be enough for basic income of 500$/month for about 30 months (in USA). It's not like you can turn Tesla into housing for the poor though with any kind of efficiency so even that scenario is very unlikely.
If you want UBI long term you would need to heavily tax the middle class - people who work a lot and provide value every day. This is what always happens with such programs and happened in my country as well (where the UBI was very limited to 125$/month and only given per child).
It's easy to point into "evil billionaires" and say to take for them but in reality you need to take a lot more from a guy who built his career for 15+ years and is now a doctor or a programmer or a small business owner. This group already pays a lot in taxes, often in excess of 50% of what they make.
"A study by White House economists released on September 23 found that the 400 wealthiest U.S. families paid an average income tax rate of just 8.2 percent from 2010 to 2018."