Either unemployment skyrockets, in the worst case causing extreme poverty and eventually riots/revolution. Or everyone agrees to lower weekly working hours and shares the income like that (which also means that wages for sure need to go up). Or some sort of UBI is implemented, so no one if forced into poverty.
The problem is that humans are breeding machines. So if you pay people just to exist, you end up with a population problem which is not pleasant to have to take other means to control. The good news is that education tends to lower reproductive rates. The bad news is that if you're paying people just for breathing (and breeding), what incentive is there to get an education?