On June 22, 1927, Charles Lindbergh flew into Dayton, Ohio, for dinner at Orville Wright's house. It had been just a month since the young aviator's first ever solo nonstop crossing of the Atlantic, and he felt he ought to pay his respects to the celebrated pioneer of flight.

Forty-two years later, on July 16, 1969, Apollo 11 astronaut Neil Armstrong was allowed to bring a personal guest to the Kennedy Space Center to witness the launch of NASA's towering Saturn V rocket. Armstrong invited his hero, Charles Lindbergh.

That's how fast technology advanced in the 20th century. One man, Lindbergh, could be the living link between the pilot of the first powered flight and the commander of the first mission to another world.

In our century, for better or worse, progress isn't what it used to be. Northwestern University economist Robert Gordon argues that by 1970, all the key technologies of modern life were in place: sanitation, electricity, mechanized agriculture, highways, air travel, telecommunications, and the like. After that, innovation and economic growth simply couldn't keep going at the breakneck pace set over the preceding 100 years—a period Gordon calls “the special century.”

Since 1970 the only notable outlier has been the exponential increase in computing power, which has trickled down to consumers in the form of the Internet and our ever present mobile devices. But in most other ways, Gordon argues, the lives of people in developed nations look and feel the same in 2019 as they did in 1979 or 1989.

This is good in one small way, though bad in most of the ways that count. Rapid and incessant change can be disorienting, and when things evolve at a more measured pace, people and institutions do have more time to breathe and adapt. But speaking as a Gen Xer, deceleration isn't what I was taught to expect. And in many areas of technology, the forward movement today feels tragically slow, even nonexistent.

Consider consumer robotics. There's enormous potential for robots to help us with housework, education, entertainment and medical care. But home robotics companies seem to keep folding: social robot maker Jibo closed in March after raising almost $73 million in venture capital, and in April robot toy maker Anki shut down after raising at least $182 million. The only commercially successful home robot, iRobot's Roomba vacuum cleaner, hit the market in 2002.

Or consider access to space. In 2007 the XPRIZE Foundation offered $30 million in prizes, funded by Google, to commercial teams that would compete to land a robotic rover on the moon. When it became obvious that no team would be able to meet the original deadline, the foundation extended the contest four times and finally pulled the plug in 2018. Although five teams had built rovers, all had trouble raising enough money to buy launch contracts. Companies such as Seattle-based Spaceflight Industries are pioneering low-cost ride sharing into space for very small satellites, but the cost per kilogram for getting large satellites and probes into orbit is still, pardon the pun, sky-high. (Israel-based SpaceIL got its Beresheet craft into lunar orbit in April, well after the competition's cancellation, but it crashed after an error during descent.)

Our century's one signature technology achievement is the iPhone. And at this point, we've had smartphones in our pockets long enough to begin to appreciate their dangers. Meanwhile the list of potentially world-changing technologies that get lots of press ink but remain stubbornly in the prototype phase is very long. Self-driving cars, flying cars, augmented-reality glasses, gene therapy, nuclear fusion. Need I continue?

Granted, these are all hard problems. But historically, solving the really big problems—rural electrification, for example—has required sustained, large-scale investments, often with private markets and taxpayers splitting the burden. In this century, we urgently need to undo some of the consequences of the last great boom by developing affordable zero- and negative-emissions technologies. That's another hard problem—and to solve it, we'll need to recapture some of what made the “special century” so special.