It's obvious if you walk around many neighborhoods in New York, San Francisco, Washington, DC, and other large cities that urban living is enjoying a revival in the 21st-century United States of America. But Census Bureau statistics also clearly show that the overall population of the United States is more suburban than ever. How can both be true?

A new analysis from Jed Kolko shows that the answer is class — a rich minority of the population is becoming more urbanized even as the overall population becomes more suburban:

The top 20 percent of the population has become a lot more likely to live in a high-density urban neighborhood, and the next 20 percent is somewhat more likely. But the bottom 60 percent — and especially the bottom 10 percent — have become far less urbanized.

Childless college graduates are moving to the city

We also see stratification by family type. People with college degrees are moving to high-density urban neighborhoods, and working-class people are moving out. People without school-age kids are moving in, and people with kids in school are moving out.

The success and failure of American urbanism

What you're seeing here is an overall pattern in which the urban revival is real but limited. There is increased demand to live in high-density neighborhoods, but those neighborhoods do not allow enough new construction for them to be affordable down the income chain. Urban neighborhoods have also not provided the kind of facilities, primarily schools and public safety, that make them attractive for the parents of older children.

As a "business model" for America's cities, this kind of makes sense.

Every time a two-bedroom apartment that used to house a working-class mom and her two kids is replaced by a dual-income childless couple who use the spare bedroom as an office/guest room, the city's tax base goes up and its need for social spending goes down. Even as the office transforms into a nursery, the fiscal situation remains far more favorable.

If four or five years later the couple, having paid taxes for years while consuming minimal social services, decamps for the suburbs only to be replaced by a new DINK (dual income no kids), then life is good. If they actually stuck around, the dynamics wouldn't be as good.

But I've lived in high-density urban neighborhoods my whole life, and I've never heard a voter or public official espouse the goal of making their city a hostile place for poor people and parents. People want — or at least claim they want — America's newly thriving cities to be engines of economic opportunity. But status quo policies are delivering the opposite result.