Urbanist contrarian Joel Kotkin thinks that the real drivers of metropolitan economies are not the hipsters in the core but the families in the burbs. Accordingly, he predicts that family-friendly cities (Houston, Dallas, Charlotte, Raleigh-Durham) will have the strongest job growth. Those cities favored by young singles (Chicago, Boston, New York, San Francisco, and Seattle) keep losing productive population in their mid-30s, departing as the kids are about to enter school. Kotkin, lays out this theory in a Wall Street Journal essay. He's taking aim at the theories espoused by Richard Florida, who argues that cities that pursue a strategy to attract the young and the hip, also known glowingly as "the creative class," will enjoy the fastest economic growth. Kotkin notes that some unlikely cities that have chased the Florida formula (Cincinnati, Baltimore, Cleveland, Memphis, Philadelphia) have enjoyed little demographic or economic growth. More plausible cities, such as Denver, Seattle, and Portland, have done better, but that may be due to other economic factors like a strong tech sector. Overall, Kotkin contends, real growth continues to go to suburbs and family-friendly places. "Married people with children tend to be both successful and motivated, precisely the people who make economies go," Kotkin says. He adds that executive recruiters emphasize cities that can hold skilled workers long term, and that means places with jobs, affordable housing, and family-nurturing communities not too distant from work. If so, the emphasis by cities such as Seattle in luring singles may be misplaced. In Philadelphia, for instance, where the downtown population has swelled in recent years, primarily due to migration of young singles and childess couples, the city has still been losing population. Now the emphasis is on retaining the middle class, by reviving traditional family neighborhoods surrounding the Center City. The new priorities are parks, playgrounds, and schools, replacing the earlier obsession with clubs, restaurants, and singles-bars. Seattle Mayor Greg Nickels was a charter member of the Richard Florida Fan Club, even bringing the charismatic professor to lecture at Town Hall. Now he's tougher on nightlife, working hard to improve schools, and looking for ways to make housing affordable for middle class families. Maybe we're witnessing a shift from the creative class to the procreative class?