What could boost urban growth? For starters, more construction in city neighborhoods. That would allow higher urban population growth, while slowing price increases. Also, higher energy prices would encourage people to live closer to work and in smaller homes. By the same token, the recent drop in oil prices, if sustained, would have the opposite effect, becoming yet another tailwind for suburbs and headwind for cities. Finally, cultural attitudes could shift in favor of renting and urban living. But is that likely? Today, the vast majority of young renters aspire to own. Homeownership remains core to the American Dream. The future of the suburbs looks bright.