Richard Longworth, a distinguished fellow with the Chicago Council on Global Affairs, fears that exactly this is happening in Chicago. The metropolitan area long sat at the center of a network of economic links crisscrossing the Midwest. They connected Chicago to Wisconsin mill towns that sent their lumber there, Iowa farmers who supplied the city’s meatpackers, Michigan ice houses that emerged along the railroads transporting that meat to New York.

“These links have been broken,” Mr. Longworth said. Of course, some remain. And antipathy toward prosperous big cities is not a new theme in history. “But this is different: This is deeper,” Mr. Longworth said. “It is also, as far as we can see, permanent, simply because the economy that supported the earlier relationships has gone away and shows no sign of coming back.”

The Rise of Global Cities

For much of the 20th century, wages in poorer parts of the country were rising faster than wages in richer places. Their differences were narrowing, a product of migration between the two and gains from manufacturing that helped lift up regions that were once deeply poor. Then around 1980, according to work by the Princeton researcher Elisa Giannone, that convergence began to stall.

Cities full of highly educated workers like Boston, San Francisco and New York began to pull away. And that pattern, Ms. Giannone finds, has been driven entirely by what’s happening with high-skilled workers: When they cluster together in these places, their wages rise even more. That widens inequality both within wealthy cities and between wealthy regions and poorer ones.

“Big changes have been happening over the last 30 years,” Ms. Giannone said. “Now we’re actually seeing the impact of them.”

Those changes have come from multiple directions — from globalization, from computerization, from the shift in the United States away from manufacturing toward a knowledge and service economy. These trends have buffeted many smaller cities and nonurban areas. The uncomfortable political truth is that they’ve also benefited places like San Francisco and New York.