See, the so-called lump of jobs fallacy really is a fallacy. Many people think that if you eliminate an existing job, the number of available jobs in the economy goes down by one. But this is simply not support by the facts. The rate of job churn in any modern economy — even Japan’s — is much, much larger than the rate of net job creation or destruction. When people’s jobs are eliminated, they almost always find new things to do, unless the country is in a deep recession.
Of course, there are costs involved with eliminating an existing position — for example, if people have to retrain. But the skill of pushing an elevator button or guarding an empty lot isn’t exactly something that requires one to go back to school. And government can help laid-off people look for work, through websites and other services.
It makes sense to be worried:
 the extreme version: automation simply makes human workers obsolete, just as cars made horses redundant
 a less apocalyptic possibility is what economists call “skill-biased technological change” — people who are technically savvy, mentally flexible and educated will reap greater and greater rewards while everyone else sees their wages decline.
→ some/all either impoverished or reduced to living off of the government dole
Although adoption of machines in the past didn’t make human labor obsolete so far:
 if it had, we’d be seeing faster productivity growth and higher unemployment
 claims that companies are substituting machines for humans more than in the past are not few, but so far the evidence remains scant
 the example of the Luddites: they could always find ever-more-lucrative jobs that made use of new tools → previous technological revolutions always ended up making the mass of humanity more valuable, not less
 reviewing economic history, new technology has complemented human labor rather than replacing it (most macroeconomic models assume that the relationship between technology and humans is basically fixed)
 though the paper by Acemoglu&Restrepofinds in MIT evidence that robots are already costing American jobs, Mishel&Bivens of the Economic Policy Institute(a think tank) examine MIT paper in detail, and note that capital investment, and use of computers specifically, tend to increase jobs, as Acemoglu&Restrepo themselves wrote
“(comparing to industrial robots – fully autonomous multipurpose machines with no human operators -) other types of capital equipment and even computers tend to increase the demand for labor…thus a very different impact on employment and wages.”
[5.1] + workers haven’t been changing occupations as much as they did in past decades — if people were losing their jobs to automation at a faster rate, we’d expect them to have to retrain more frequently
[5.2] productivity growth and corporate investment in IT has fallen, which also doesn’t fit with a story of accelerating automation (actually an investment drought in rich countries, as companies sit on cash)
[5.3] negative impact of Chinese competition on U.S. jobs was more than three times larger than the effect of robots
there’s no guarantee that future technology will work the same:
 robot revolution may be more of a long-term concern, driven by the rapid advances in machine learning → a world machine do anything better than human? / capital-labor substitutability would increase dramatically — you don’t need a human to operate the machine tool or the computer (← it’s always hard to predict future technology)
 before 1800 before Industrial Revolution, an economist would conclude technologies of the past have never allowed the mass of the species to escape from poverty and malthus trap → new technologies were qualitatively different (though resulted in an abrupt acceleration of wealth generation)
 If the elasticity of substitution between capital and labor (how easy it is to replace humans with machines) goes up, labor’s share of income can go down and down + Skill-biased technological change rewards the top workers while punishing everyone else
 more extreme, huge inequality: people who won at the beginning of the artificial-intelligence revolution would start off in a privileged position, able to outcompete new entrants in winner-take-all markets / people who started out with the capital would amass essentially all the wealth in society, while those who started out with less would be out of luck.
 there will always be more work for humans to do, despite more absurd, esoteric jobs ← the problem is that such jobs will not necessarily pay a living wage ← if capital-labor substitutability increases dramatically, wages may fall a lot ← either humans will survive via redistribution, or they won’t survive at all ← redistribution depends on politics, and in an age of robots, the masses may have very little power to compel the wealthy to give up even a small sliver of their wealth
“Once the military became robotic, revolution became impossible.”
when is next difference? (source)
more on real, pressing problems:
 Inequality in developed countries remains severe and potentially harmful to civic society.
 The productivity slowdown is disturbing and imposes a drag on growth.
 Reduced economic dynamism, including falling startup rates and less job-switching, is a concern.
 Monopoly power is a looming threat to the health of the economy.
 Although wages have been rising recently, those gains come after many yearsof stagnation or decline.