Or facilities optimize to produce less trash so they can handle the newer trash load with less staff instead of paying extra.
> The price of food and of housing everybody would be dirt cheap ... then it will be very very cheap in an ideal free market.
We don't live in an ideal free market.
Food is extremely cheap to the point that the USG (effectively) sets price floors which prevents it from falling further. People do live on $3/day.
SROs not in say NYC are cheap as well. Everybody trying to live in the same major cities will never be cheap.
> Why would we need UBI then?
Activation Energy - Many people have no choice to work a dead-end or low-paying job because they cannot afford to take a break to find higher paying work more suited to their skills.
Opportunity Cost - The geologist example from above where you need to hide information from others so you don't suffer.
Societal unrest - Literally right now there's a president in the US whose base is upset about how the technological progress was not shared with them to the point they want to throw away any current advantages to go backwards in time.