More generally, cheap areas often means economic underdevelopment or decline, which leads to social problems and annoying neighbors (on account of drinking, unemployment and other issues). On the plus side, there's less traffic, because people aren't as busy going to places to make and spend money as they are in economically vibrant areas.
It also means that there’s less money available for infrastructure maintenance. While a city is expanding, the majority of the housing is occupied, and the infrastructure to support new housing doesn’t yet require replacement. As a city contracts, there are more unoccupied houses and vacant lots. There’s still the same length of water, sewage, and power lines along the length of a street, but fewer residents to pay for it as it becomes old enough to need repairs/replacement.
