Very good movie on the Pruitt-Igoe housing project in St. Louis, "The Pruitt-Igoe Myth". Great explanation on failure not due to single cause as our cause-and-effect western cultural conditioning would have us believe. There were many factors and maintenance was one of them. We are trained to look for single remedy for an ailment and we do same with social problems. Hope some day we see the interconnectedness of the social fabric.
The "slums" were cleared away for boulevards or later, 'modern' blocks and either way, we look back to see the building fabric was usually fantastic, only the maintenance was bad. One day a block of flats is 'poor', and the next, 'rich'; with no change to the buildings other than upkeep.