> So to do true UBI, you’d also have to raise taxes quite a bit.
That's correct.
You'd have to raise taxes across the board. There is a lingering assumption that we can tax billionaires and get UBI, but more simple math shows that won't work either. Even if you seized 100% of the net worth (not just cash in the bank) of all US billionaires, you couldn't provide poverty-level wages to everyone for very long.
In practice, this means that a UBI program would turn into a tax rate program. You might "receive" $15K in UBI, but your middle-class taxes would go up by $20K per year. So you're technically getting UBI, but your taxes have gone up to pay for it to go to people in lower tax brackets.
If US GDP is ~30 trillion, the program would have to capture ~20% of that to achieve your target.
Do check my math, I’m not sure I’ve got this right.