The driverless 18-wheeler is coming, most technologists agree. Great news for shippers. Lousy news for truck drivers.

About 3.5 million Americans earn their living driving a truck, and millions more drive taxis, Uber cars, delivery vans and buses. What will they do when technology eliminates the need for a human behind the wheel?

That’s been the topic of more than one high-level discussion at this year’s Milken Institute conference in Los Angeles, the annual gathering of financiers, business leaders and other potentates. Most of the 1 percenters gathered here won’t be harmed at all when trucks drive themselves. But they worry about those who will be harmed, and what the blowback might be. “The Industrial Revolution produced Marxism,” warned Princeton professor Anne-Marie Slaughter, pointing out that moments of great progress also leave some people behind—and sometimes create tsunamis of populism that bring down elites.

Technology has been displacing American workers for at least two decades, and the disruptive churn finally produced a political shock in the election of Donald Trump as president. So the fate of truck drivers 10 or 20 years from now is something already familiar to millions of factory workers and others whose jobs are now done by algorithms, robots or other machines. But this trend doesn’t seem to have crested yet, and could intensify rather than ebb. “We are seeing the decline of good-paying jobs that support middle-class lives,” Slaughter, who is president of the think tank New America, told Yahoo Finance. “We need to tell people to prepare for a different future.”

There’s currently a shortage of truck drivers, which might be why the potential demise of the occupation gets the attention of people thinking hard about the future: going from a labor shortage to zero employment would be a stark economic devolution, if it ever happens. Technology creates new jobs and kills old ones all the time, of course; what’s different now is the speed of technological change and the long lag while workers and government policymakers try catch up, which can stretch to a generation.

In theory, when old jobs go away, people are supposed to develop new skills that are more in-demand, and move to places where jobs are more plentiful. “The big question is, can we move the truck drivers from the truck driving roles to the new roles in the economy,” Aaron Levie, CEO of the cloud-computing company Box, said at the Milken Conference. “We’re optimistic that the path ahead is going to represent a bunch of opportunity for a lot of people.” One program, in Kentucky, even teaches out-of-work coal miners to do computer coding, so they can take longer-lasting jobs in the digital economy. Truck drivers might do the same once their obsolescence arrives.