Adair Turner , a senior fellow at the Institute for New Economic Thinking in London, argues that the economy today resembles what would have happened if farmers had spent their extra income from the use of tractors and combines on domestic servants. Productivity in domestic work doesn’t grow quickly. As more and more workers were bumped out of agriculture into servitude, productivity growth across the economy would have stagnated.

“Until a few years ago, I didn’t think this was a very complicated subject; The Luddites were wrong and the believers in technology and technological progress were right,” Lawrence Summers , a former Treasury secretary and presidential economic adviser, said in a lecture at the National Bureau of Economic Research five years ago. “I’m not so completely certain now.”

The growing awareness of robots’ impact on the working class raises anew a very old question: Could automation go too far? Mr. Acemoglu and Pascual Restrepo of Boston University argue that businesses are not even reaping large rewards for the money they are spending to replace their workers with machines.

But the cost of automation to workers and society could be substantial. “It may well be that,” Mr. Summers said, “some categories of labor will not be able to earn a subsistence income.” And this could exacerbate social ills, from workers dropping out of jobs and getting hooked on painkillers, to mass incarceration and families falling apart.

Silicon Valley’s dream of an economy without workers may be implausible. But an economy where most people toil exclusively in the lowliest of jobs might be little better.