JOEL KOTKIN: How Can We Be So Dense? Anti-Sprawl Policies Threaten America’s Future.

Among university professors, government planners and mainstream pundits there is little doubt that the best city is the densest one. This notion is also supported by a wide number of politically connected developers, who see in the cramming of Americans into ever smaller spaces an opportunity for vast, often taxpayer-subsidized, profiteering.

More recently density advocates span a much-discussed study of geographic variations in upward mobility as suggesting that living in a spread-out city hurts children’s prospects in life. “Sprawl may be killing Horatio Alger,” quipped economist and New York Times columnist Paul Krugman.

Yet the study actually found the highest rates of upward mobility not in dense cities, but in relatively spread-out places like Salt Lake City, small cities of the Great Plains such as Bismarck, N.D.; Yankton, S.D.; and Pecos, Texas — all showed bottom to top mobility rates more than double New York City. And we shouldn’t forget the success story of Bakersfield, Calif., a city Columbia University urban planning professor David King wryly labeled “a poster child for sprawl.” Rather than an ode to bigness, notes demographer Wendell Cox, the study found that commuting zones (similar to metropolitan areas) with populations under 100,000 — smaller cities that tend to be sprawled by nature — have the highest average upward income mobility.

Well, it’s cheaper to live in places like that, meaning that there’s more capital available to individuals.