There have been experiments with remote ATC, for small airports especially. Here is a video: https://youtu.be/Ii_Gz1WbBGA?feature=shared

I wonder how they’re doing today.

There is work being done on remote tower systems (RTS).

https://www.faa.gov/airports/planning_capacity/non_federal/r...

ATC includes “Center” which manages planes once they’re out of the airport, and those can (and are) handled by controllers far removed from the area they’re controlling.

London famously has ATC centralized: https://en.wikipedia.org/wiki/London_Area_Control_Centre