UBI has to be significantly lower than the average taxes paid. If it isn't the books don't balance and eventually inflation kicks in hard and eventually it reaches that equilibrium. If nobody works then taxes are $0 and UBI is $0.

So if you do the math using fairly roughly you'll find that the US can support a UBI of about $1500/month without significant inflationary pressure. That'll pay your rent (if you're sharing an apartment) and cover groceries (if you mostly live on rice and beans). If you want a car, vacations or the latest iPhone you have to work. So most would work and build those cars et al.