The question is how many people making 200k will, given the option, take the free 20k and not work, therefore paying no taxes.
A lot of people making 200k+ have grown accustomed to the kind of lifestyle that income enables (nice house, nice car, nice restaurants, foreign vacations, sending their kids to private school, etc)-and couldn’t afford to keep doing that on 20k. Given the choice between 200k job and 200k lifestyle, and no job and 20k lifestyle, I think the majority of people already accustomed to the first option would choose to continue in it. Also, a lot of people on 200k+ already have more than 20k of savings/investments, so if they are willing to run those down, they could choose the no job/20k lifestyle today, no need to wait for UBI-yet few do.
As another way to think about it - do bonuses disincentivize workers? At least personally that just makes me want to do more because it's freeing up a bunch of mental energy I need to spend on finances, and then I can focus on important things aside from basic survival
I don't personally know anyone that would opt for 20k/yr over their current salary, but I know several people making over 250k that want to make more to drive their sense of societal value.
I don't agree with it, but if you want to maintain the threat of poverty to force labor you can still do that with UBI
$20k is not quite enough, but I can tell you that I lived the life of my dreams on $25k a year from 2016-2018. If I could guarantee that lifestyle forever I would take it over my current $300k+ job in a microsecond.
But government policy (even that notionally of a Constitutional character, which most UBI proposals wouldn’t be) isn’t a permanent guarantee (see abortion rights for a recent example), and if that was really true, it doesn’t take long living a $25k lifestyle on a $300k income to be able to save and make yourself a firmer guarantee of a $25k lifestyle forever than government policy would ever do.
Approximately no one does it, because as much as people making lots of money might rhetorically appeal to the attractiveness of such an idea, no one actually making that money now feels it enough to act on it.
The people who would be content to rely on minimal poverty support are, largely, doing that already, since we have such programs now and they have a much stronger disincentive to additional income than would exist with UBI due to means testing, which takes benefits away rapidly (sometimes more than 1:1) with additional income.
It's much harder to live a $25k lifestyle while working a demanding full-time job than it is while having all your time free, though.
- You can choose a low cost of living area.
- You have plenty of time to cook all your own meals.
- You can fix your own car.
- You can travel during off-times when prices are lower.
And so on.
Almost certainly the same number as are making 200k now that cease additional effort beyond what is necessary to make 20k, i.e., 0.
Probably even at lower levels more people would work (at least in the open economy paying full taxes) than dobcurrently, since pushing any clawback of benefits from the low levels and high marginal rates that they kick in with means tested benefit programs to somewhere higher on the income spectrum at a lower marginal additional rate reduces the disincentive to additional work compared to the status quo.
I don't think so, because making $20k usually requires much more than 10% of the time and effort needed to make $200k.