Fundamental changes in American life may turn today’s McMansions into tomorrow’s tenements.

In the Franklin Reserve neighborhood of Elk Grove, California, south of Sacramento, the houses are nicer than those at Windy Ridge—many once sold for well over $500,000—but the phenomenon is the same. At the height of the boom, 10,000 new homes were built there in just four years. Now many are empty; renters of dubious character occupy others. Graffiti, broken windows, and other markers of decay have multiplied.

The decline of places like Windy Ridge and Franklin Reserve is usually attributed to the subprime-mortgage crisis, with its wave of foreclosures. And the crisis has indeed catalyzed or intensified social problems in many communities. But the story of vacant suburban homes and declining suburban neighborhoods did not begin with the crisis, and will not end with it. A structural change is under way in the housing market—a major shift in the way many Americans want to live and work. It has shaped the current downturn, steering some of the worst problems away from the cities and toward the suburban fringes. And its effects will be felt more strongly, and more broadly, as the years pass. Its ultimate impact on the suburbs, and the cities, will be profound.

he suburban dream began, arguably, at the New York World’s Fair of 1939 and ’40. “Highways and Horizons,” better known as “Futurama,” was overwhelmingly the fair’s most popular exhibit; perhaps 10 percent of the American population saw it. At the heart of the exhibit was a scale model, covering an area about the size of a football field, that showed what American cities and towns might look like in 1960. Visitors watched matchbox-sized cars zip down wide highways. Gone were the crowded tenements of the time; 1960s Americans would live in stand-alone houses with spacious yards and attached garages. The exhibit would not impress us today, but at the time, it inspired wonder. E. B. White wrote in Harper’s, “A ride on the Futurama … induces approximately the same emotional response as a trip through the Cathedral of St. John the Divine … I didn’t want to wake up.”

The suburban transformation that began in 1946, as GIs returned home, took almost half a century to complete, as first people, then retail, then jobs moved out of cities and into new subdivisions, malls, and office parks. As families decamped for the suburbs, they left behind out-of-fashion real estate, a poorer residential base, and rising crime. Once-thriving central-city retail districts were killed off by the combination of regional suburban malls and the 1960s riots. By the end of the 1970s, people seeking safety and good schools generally had little alternative but to move to the suburbs. In 1981, Escape From New York, starring Kurt Russell, depicted a near future in which Manhattan had been abandoned, fenced off, and turned into an unsupervised penitentiary.