When a city turns its back on the middle classThis essay by Joel Kotkin is the best I've seen summarizing the slow decline cities go into when they turn their back on the middle class, using LA as a case study.
"Across the country, major cities are continuing to lose middle-class residents as they flock either to the surrounding suburbs or to less congested, more affordable, and more business-friendly smaller cities, particularly in places like Nevada, Arizona, Texas, and Florida. The group that is leaving--upwardly mobile people in their thirties and forties--represents a particularly important part of the urban mix. Historically, when this strata has abandoned cities, urban society has shifted toward a more bifurcated makeup: the wealthy few residing among a growing underclass. This occurred in late imperial Rome, in seventeenth-century Venice, in eighteenth-century Amsterdam--and has become a common prelude to urban disaster in American cities during the past half-century.
Why is this a troubling trend? Because cities that are stratified between the very wealthy and the very poor cannot fully exercise their role as centers of American economic, social, and cultural life. For one thing, such cities offer little room to the upstarts who historically reshape urban centers--a highly bifurcated city is less likely to produce great entrepreneurs or innovators. The wealthy generally bypass public institutions--parks, libraries, public schools--because they can create their own; those institutions, used only by the poor, inevitably deteriorate, and a vicious cycle is born. This is particularly important with regard to the public schools, which were once the primary means of social uplift in cities (and should, at least in theory, provide the glue that holds a city together across ethnic and economic lines). "
Houston so far has avoided these mistakes, although constant vigilance is required. I'm sure each individual decision made by these cities made sense at the time, but after adding them up along a gentle sliding slope, they ended up somewhere they didn't really want to be.