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.

By 2005, real language-processing companies existed in Las Vegas, a Boston suburb, Pittsburgh, and a small city outside Salt Lake City -- not one of them in Silicon Valley. Each was funded independently, wherever it already existed, by capital chasing one urgent national need.

Route 128, completed in 1956, was the nation's first real high-tech corridor -- built on defense money five years before Silicon Valley. By the 1980s it should have been Silicon Valley; a 1994 study found Silicon Valley's open networks simply out-adapted Route 128's closed corporations.