Cities are much different than country roads. Cities have gangs and other predators in close proximity. Cities have entertainment, theater, sports events, and shopping districts. This is how they get the money to prosper. Without lights, nobody would leave their homes and venture out and/or go to those events. It’s much too dangerous to walk around in the city without lights.
I’m not talking about pedestrian areas. I’m saying that there is no reason that the interstate needs to be lit like your living room, just because its inside city limits.