There’s little mystery about where people are heading, or why: They are mostly moving toward sun and some semblance of affordability. The major Texas metros—Houston, Dallas, San Antonio, and Austin—have collectively grown by more than 3 million since 2010. The most popular destinations for movers are now Phoenix, Dallas, and Las Vegas, which welcome more than 100,000 new people each year.

Until recently, domestic out-migration was counteracted by international immigration. From 2010 to 2018, immigration accounted for more than 100 percent of population growth in the New York, Chicago, and Philadelphia metros, and more than 80 percent of population growth in the Los Angeles and Boston areas, according to analysis by the Brookings Institution demographer William Frey.

What was celebrated as an urban renaissance was in large part an urban-immigration renaissance. In New York City’s five boroughs, the foreign-born share of the population increased from 18 percent in the 1970s to nearly 40 percent today, approaching its early 20th century highs. Following the 1965 Immigration Act, Los Angeles County’s immigrant population saw almost the exact same increase. Incidentally, this is a good thing: Families and young people moving to the U.S. from places such as the Dominican Republic, China, Mexico, and Vietnam enrich their new neighborhood’s culture, provide necessary labor—both “high skill,” like engineering, and “low skill,” like home health assistance—and generate a disproportionate share of new businesses.

In the past few years, however, population growth in the New York and Los Angeles areas has stalled. For the first time in decades, the nation’s two biggest metros are getting smaller at the same time. Immigrants aren’t coming in at the same rate they used to, and native-born Americans are leaving even faster. Why?

An easy answer is that America’s smaller metros have cheaper houses. This is especially true recently for Los Angeles, where insufficient housing development has contributed to a 75 percent increase in housing prices since the end of the Great Recession. What’s more, smaller cities and suburbs now offer similar knowledge-work jobs in a familiar residential aesthetic. In the past decade, urban developers, working off the Instagram blueprint, have standardized an MVMP—Minimum Viable Millennial Product—so that the move from Brooklyn to Boise means trading one set of hipster coffee shops, fast-casual joints, and cocktail bars for another set. Even the ground-floor retail differences between various metros becomes less important as more shopping moves online, where residents of every zip code are looking at the same social-media catalog and visiting the same digital mall.

To see what’s more deeply afflicting these metros, it’s useful to understand the plight of Chicago, whose growth after the Great Recession was just a blip in an otherwise long period of decline. Some of Chicago’s problems are unique among large metros. It sits on the far hip of the Rust Belt, hundreds of miles from the coastal economic juggernauts, and it has a homicide rate twice that of New York or L.A.