In the early 2000’s there was a documentary on Hyundai’s fully automated factory. Required 3 full time workers, all of them maintenance. Every system had redundancies, to prevent the line from shutting down. Parts were delivered by truck (on special trailers that coupled to specific docks that automatically supplied the assembly line) or were made on site. It took 16 hours to fully assemble a car from start to finish and once the assembly line was full, a new car rolled off the line every 24 minutes.
It was something incredible to watch, as the factory was a closed ecosystem. Cameras filmed from behind observation windows used to monitor the activity. Even if an assembly robot was to break, the line would halt, the faulty machine was rolled out automatically through a maintenance line/door and the spare would role in, in a matter of seconds.
It was sci-fi material.