The "why workers" is partially history and social contract as a framework for incentives which has a long legacy. If they contribuite to the system then they have a claim to the basics. If they don't why bother working?

If they were voluntarily idle then there would be a harsh factual basis of not being enough to feed them when there was work to be done. That was the logic of the past anyway. It may not be a right or good answer but it is /a/ reason.

Obviously things change with time and we are on an appatent trajectory to an "awkward middle" of both needing people to do some advanced work and outrunning useful tasks performable by everyone. Incentivizing upskilling to those who can perform non-automatable jobs while avoiding a defacto fixed underclass makes it extra awkward.