That would mean that anyone who was out of a job in the city would either need to leave the city or prey on the people within the city who still have money.
Your proposal would lead to a huge de-population of the cities. It would also mean that if by some weird series of events you became unemployed for a while, and could not find a job, you would be forced out to work the fields.
It's much easier to start working the fields than to get back to society. When you need to work for minimum wage every day, you don't have time to find that programming job you're looking for.