The suburbs and the assumptions that enabled them to grow are collapsing, according to Benfield.
"[I]n between, say, 1960 and 2000, many central cities were in severe decline, due to "white flight" and all sorts of perceived urban problems. But for some tragic exceptions like Detroit, that decline now has either slowed dramatically or reversed. In D.C., for example, the central city is growing again after 50 years of decline and ironically, a new concern of some is that "white flight" is now to the city, not away from it. New York, Philadelphia, Indianapolis, Houston, Austin, and San Antonio also grew. This is where the change is.
In addition, the distinction between "central city" and "suburb" is simply not what it once was. Inner-ring suburbs now are part of the central city in every way other than the arbitrary jurisdictional lines that mean little economically or environmentally. In his blog West North, my friend Payton Chung points out that the supposed "suburban" district of Friendship Heights Village, in Maryland but adjacent to the D.C. city limits, is 'the single most densely populated place in the entire country, with 79,556 residents per square mile. Even Manhattan only clocks in at 69,468 per square mile.'"