Hatred is more powerful than a desire for sewage treatment. Things will return to subsistence farming, supplemented by hunting small rodents.
Here in NJ cities are desperately appealing to whites to come back; Newark NJ was basically offering to build them a fortified compound (a “teachers village”) to do so. When one of my young sons asked why the blacks on the TV were tearing up either Ferguson or Baltimore (they all look the same to me), I responded that they did it because they knew white people would clean it up. As if on cue, the next morning he came downstairs to prepare for school and a white tow truck diver was flatbedding one of the burned cars out of there.