Nearly a century ago, in 1920, the Census Bureau caused a ruckus when it announced that for the first time a majority of Americans lived in cities — even though its definition of a city included every hamlet with a population of 2,500 and above.

Today a majority of Americans live in what are by any reasonable definition very large cities, metropolitan areas with populations above 1 million. But the urban planning profession remains fixated on just one small portion of these metropolises, the central city downtowns, though none outside New York contains more than 10 percent of metropolitan area jobs.