It’s late-ish at night. The masses are sleeping and the security cameras are peeping in their respective store fronts.
Nearly no one noticed the one light flickering dismally until it burned out, it’s last sparks of life keeping the street bright.
With all the people tucked away in their beds, couches, sleeping bags and street corners, only one lonely wandering figure saw the light expend it’s last breaths.
Within the quiet confines of the darkness brought on by dead bulbs, this being keeps the world bright.
They replace every lightbulb with a successor, and take the dull ones back to the vault to be tinkered with, and eventually reissued.