For decades, we’ve turned to Silicon Valley to show us the future of American endeavor. Optimism flowed from the Bay Area’s evangelists but also from Washington. “In the new economy, human invention increasingly makes physical resources obsolete,” President Ronald Reagan said in a 1988 speech that heralded the promise of the computer chip. In the ’80s and ’90s, Democrats such as Al Gore made up a new generation of liberals—named “Atari Democrats,” after the early video-game company—who believed computer technology would provide opportunity on the scale of the New Deal. The internet age was hailed as a third industrial revolution—a spur for individual ingenuity and an engine of employment.

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On these counts, it has not delivered. To the contrary, the digital age has coincided with a slump in America’s economic dynamism. The tech sector’s innovations have made a handful of people quite rich, but it has failed to create enough middle-class jobs to offset the decline of the country’s manufacturing base, or to help solve the country’s most pressing problems: deteriorating infrastructure, climate change, low growth, rising economic inequality. Tech companies that operate in the physical world, such as Lyft and DoorDash, offer greater convenience, but they hardly represent the kind of transformation that Reagan and Gore had in mind. These failures—perhaps more than the toxicity of the web—underlie the meanness and radicalism of our era.

Decades from now, historians will likely look back on the beginning of the 21st century as a period when the smartest minds in the world’s richest country sank their talent, time, and capital into a narrow band of human endeavor—digital technology. Their efforts have given us frictionless access to media, information, consumer goods, and chauffeurs. But software has hardly remade the physical world. We were promised an industrial revolution. What we got was a revolution in consumer convenience.

The original Industrial Revolution freed humanity from the centuries-long prison of slow economic growth. In the early 19th century, productivity and income were skyrocketing, first in England and soon throughout Europe. While the transition was brutal for many, the gains were broadly shared: Real wages for the working class doubled in the first half of the century, and life expectancy at birth rose dramatically in the second half.

In the computer age, the economy has trended in the opposite direction. If American productivity had continued to grow as it did from Harry Truman’s election to Richard Nixon’s resignation, the 2013 economy would have been about 60 percent larger. (Dividing those gains equally would have given the typical middle-class household a bonus of roughly $30,000 a year.) Instead, income growth from 1973 to 2013 was 80 percent slower.