Orders of magnitude more than we have now
> and immigration (only citizens get UBI). Of course this is a major downside, because you end up with a slave class unless you make sure those immigrant workers are well protected.
... Uh... yeah I would prefer not to have a slave class
What do you think we have now, where lower class people need to work to survive? If slavery is having the option between work or death, then I don't see how our current economic setup is not producing slaves. Sure, we don't treat the lower class as property (at least not normally), but they are definitely forced to work under any reasonable definition.
It's arguably the most regressive fiscal system one can imagine. A class of people who must earn an entire cost of living paycheck to net zero with their non-working, unskilled citizen equivalents.
People are not property and they are most certainly not forced to work. Wanting things and needing money to buy the things you want is not “being forced”.
> We need people to do low level jobs
Is solved through automation and immigration (only citizens get UBI). Of course this is a major downside, because you end up with a slave class unless you make sure those immigrant workers are well protected.
Your point 2 has already happened. But the wealth still remains here in the US. So if that wealth were redistributed to the poor it would actually make things better.