> If the basic income wasn't adjusted for different areas, you would probably see some areas become rich elite enclaves while other areas become basic income ghettos.

Some places have been rich elite enclaves and other places ghettoes for pretty much the whole history of human civilization; its pretty clearly already the case now (and not just between widely geographically separated areas like San Francisco and Grover, NC; its true within cities like San Francisco -- or any other city of substantial size anywhere in the world.)

A flat national BI doesn't create that problem, it just fails to completely eradicate it (it likely does reduce it by reducing overall income inequality, so, as far as the issue is even relevant, its one in favor of adopting BI, not against it.)