Hopefully there will be careers for people in 20 years.
Doubt.
UBI is distributed by the government directly, so it's basically a question of what gets taxed, how much inflation results, and whether that inflation and taxation proves more unpopular than the UBI is popular.
There are a lot of counterarguments to a high minimum wage, some even from UBI proponents, but none of them are "they're taking my money" because that doesn't make sense in the context of a minimum wage.
But that still doesn't apply to a UBI, because a UBI is universal. The person buying the Big Mac or running the small business gets it too, and the breakeven point would be around the average income, so you don't have the problem the minimum wage has where the people paying the cost are often the people who weren't making that much money to begin with.
In optimistic scenarios, if AI can do so much that nobody's even getting paid to make robots, then AI are making robots that also makes the cost of living lower.
In practice, I think that the path from here to there is unstable.
Minimum wage is a price control. Price controls are trash economics and should not be used. They're a political issue in the US because a federal minimum wage is doubly counterproductive, since different states have a different cost of living. But because of that the states with a higher cost of living see a smaller deleterious effect from a higher minimum wage. Then representatives from those states can claim to want to raise the minimum wage so they can paint their opponents from the lower cost of living states as the villains when they fight against it. But nobody really wants to increase it because it's a bad policy, most of the proponents are from states whose constituents wouldn't even be affected because their state already has a minimum wage in excess of the federal one, the proponents just want to make their opponents vote it down again so they can cast aspersions over it.
A UBI is equivalent to a large universal tax credit. A slight majority of the population would receive more than they pay on net because the median income is slightly below the mean income, which creates a large base of support. If everyone voted purely in their own personal financial interest it would have simple majority support. Meanwhile most of the people who would end up paying on net would only be paying slightly (because they make slightly more than the average income), and in general the net payers are a very large diffuse group with no common interests or organizational ties to one another.
A UBI is a thereby easier to bring about than either of those other things.
It doesn’t really make sense to me to live in a world where people are given money by the government while simultaneously expected to pay taxes. Its a high overhead when the same could be achieved by printing money and handing it out to everyone equally (which acts as a redistribution of wealth same as taxing the rich and paying credits to the poor, since it devalues the dollar as more supply is added)