In recent years, an overhyped counterrevolution has emerged in America. Millennials from the suburbs and their empty-nester parents have been flocking to certain desirable urban neighborhoods. This has led to a lot of chin-pulling about “demographic inversion,” wherein the cities become richer and whiter and the suburbs more non-white and poor. Skeptics note that suburbs are in the aggregate still richer and whiter than central cities and most middle-class families still settle in suburbia.

This sociological debate misses the important environmental question: What will we have achieved if we simply change the demographic complexion of who lives in walkable urban areas and who doesn’t? The answer is nothing. For the urbanist movement to be worthy of its name, the end result has to be that a higher percentage of Americans are actually living in central cities, and that the residents of both cities and suburbs represent the full spectrum of American life.

The evidence suggests that a combination of bad public policies is instead causing poor residents to be priced out of the most popular cities by well-heeled newcomers. Consider Annie Lowrey’s report on low-income renters in Tuesday’s New York Times. They are being squeezed by an economy where all the gains accrue to the top and new housing is built at the high end. Gentrification also brings wealthier renters into poor urban neighborhoods, bidding up the price of existing housing. Writes Lowrey:

The number of renters with very low incomes — less than 30 percent of the local median income, or about $19,000 nationally — surged by 3 million to 11.8 million between 2001 and 2011, according to a report released Monday by the Joint Center for Housing Studies at Harvard. But the number of affordable rentals available to those households held steady at about 7 million. And by 2011, about 2.6 million of those rentals were occupied by higher-income households. …