You don’t really make a case for or against Universal Basic Income, with the exception of the anti-tech backlash you see coming, which argues for a UBI. See Josh Jones’ Open Culture piece on this with arguments from Elon Musk and Alan Watts.
The other approach that governments have taken when masses of people are unemployed is job guarantees, which leads to an increase in government work (See pre-austerity Greece, or pre-crisis Venezuela, for example.) The push for jobs in infrastructure construction is such an approach.
I favor Watts’ argument, answering the question ‘who is going to pay for Universal Basic Income?’, which is ‘The machine is going to pay for it’. The productivity of automation can be taxed to support those thrown out of work, and potentially made unemployable.
What are people for in a world that does not need their labor, and where only a minority are needed to guide the ‘bot-based economy?
Yes, the solution is a system based on the duality that Kevin Kelly envisions, that machines are for answers and humans are for questions. But the rate of change is too fast — as you point out, Ross — for today’s taxi driver or insurance adjuster to make a graceful transition to question asking as a career.