This kind of 80/20 problem feels like a characteristic story of our low-productivity-growth era. It’s not that we’ve ceased to make scientific progress; it’s that our research keeps failing to translate into the kind of dramatic real-world change that we learned to expect from earlier expansions of human knowledge. Across a range of fields we’re constantly being teased by the promise of the big change — the alternative-energy economy, the cure of Alzheimer’s or cancer — and getting, instead, a lot of impressive specialized innovation. Which is not a small thing if your disease is cured by that specialized innovation — but on the societal scale, it’s not the acceleration and turbulence that Yang’s prescription assumes we will experience…

But if long expansions are actually as hard to generate as they appeared before the 18th century, then we shouldn’t expect a return to pre-1970s conditions, in which all our 80/20 problems suddenly get solved with Edisonian rapidity. (Though Lee himself thinks self-driving cars may be closer than the new pessimistic mood believes.)

Instead we should anticipate an age of slower growth, in which, as Lee wrote, “the living standards of mature postindustrial civilizations … converge on a sustainable level” instead of leapfrogging one another, and many new inventions are like the robot who shows up in an early episode of the near-future HBO show “Years and Years,” in a scene that promises Isaac Asimovian scenarios until it turns out that the robot’s owner just uses him the way so many people use the internet.