We sort of can, but it's mostly temporary on a long term scale unless you're talking about areas really far from the core of a metro. When more people move to a

We sort of can, but it's mostly temporary on a long term scale unless you're talking about areas really far from the core of a metro. When more people move to an area, there is (generally) more economic opportunity. With that comes rising land values and demand to live in that area. As cities grow, expand, and generate wealth for the residents, they envelop the suburbs, and development makes those suburbs more urban. If you keep those suburbs as single family housing, their value goes up tremendously at the cost of everyone else. It is not beneficial for the community at large to have these single residences in areas that could provide jobs, services, organizations, to many more people. Having more people also increases the tax base for a city compared to a single family.