It is NOT about enabling "a modest life" or stopping people from working! On any serious UBI proposal everyone is still incentivized to work.
This is, IMO, why UBI has to be timed almost perfectly for when the AI is ready to be the one who does the work.
That is what earned income tax, payroll taxes, and Medicare and Social Security taxes are.
If you believe this, then surely you also believe pension plans are the devil? If we can't have UBI then we can start by tearing away pension plans for all of the old people my tax money is being wasted on.
But yes National pensions can have the same problem, as is currently the case in France. The elderly vote themselves higher and benefits, waiting to back breaking taxes on the diminishing number of middle-aged workers