The problem is not money: it's consumptionism. There's no point to paying people to do most of the jobs they do now, anyway: the Economy of Stupid has fed too many people already, and the 'employers' lobby to keep producing more of these fattened cattle to justify CAFOs (cities) that shovel money and corn into the cars they buy to go to places that don't need any more people (or cars).

Before UBI, there needs to be VAT/sales taxes large enough to cover all of civilization's overhead costs (including good health, education for usefulness to planet, and sensible reproduction/childcare). Unless everyone sees the cost of buying a life(and choosing whether to buy one or make one), what's the point of paying them to be alive?