Following this thread to its ultimate expression, maybe the USA will become the UCA and the UFA.
How would the lower population of the United Farms of America get any business done? They’d have to have trade agreements with the United Cities of America, in exchange for food.
Immigrants are welcome to live in UCA, but they’ll only find work in UFA.
UFA will have no taxes, so no roads or schools or police either. Children who aspire to a life off the farm will have to renounce citizenship and move, before the 5th grade.