The U.S. market has never been more focused on one single bet—but AI’s payoff will likely take decades

(Credit: Courtesy of Ming Lu)

Americans have placed an unprecedented bet on the transformative power of artificial intelligence. The past 50 years of economic history suggests it won’t pay off, at least not on a timetable the market expects.

Not since the Gilded Age—when, in 1885, railroad stocks accounted for more than 80% of active trading on the New York Stock Exchange—has the U.S. economy wagered so much on a single theme. When that bubble burst in the Panic of 1893, a third of railroads went bust, more than 500 banks failed, and the economy plunged into a four-year depression.