IRS tax-return data and the Census Bureau's own county estimates agree on the same real numbers: Los Angeles and Chicago lost more people than San Francisco after 2020, by a wide margin. The city that became shorthand for pandemic flight was the one with the smallest population to lose it from.

The closest real precedent for AI-driven job loss isn't a labor-market model -- it's the Great Migration, when cotton mechanization helped push six million sharecroppers off Southern farms and into Northern cities. Whose job disappeared usually tracked class, not race -- except when it was policy, not the economy, doing the displacing. Newark's Central Ward still hasn't fully recovered from that difference, sixty-plus years later.

In 1919, a Black teenager drowned in Lake Michigan after crossing an invisible segregation line, and the riot that followed killed 38 people. In 1962, the city made that same line physical -- rerouting the Dan Ryan Expressway around a White neighborhood instead of through it, still measurable today as a 30-year life-expectancy gap between two Chicago neighborhoods nine miles apart.

The world's largest futures exchange by volume traces back to farmers dumping grain into Lake Michigan in the 1840s because storing it cost more than it was worth. Chicago merchants organized the Board of Trade in 1848 to fix that -- the direct ancestor of the $11.6 billion 2007 merger that created CME Group.