(Photo by: Hendrik Schmidt/picture-alliance/dpa/AP Images) A robotic welding system for Volkswagon car body shells is featured at the Industrial Museum in Chemnitz, Germany. T he inadequate quantity and quality of American jobs is one of the most fundamental economic challenges we face. It’s not the only challenge: Poverty, inequality, and stagnant mobility loom large, as well. But in a nation like ours, where wages and salaries are key to the living standards of working-age households, all these challenges flow from the labor market problem. OK, but this is a supposed to be an article about technology. What’s the linkage between technology and this fundamental problem? As a D.C.-based economist who’s been working on the issue of jobs and earnings for almost 25 years, trust me when I tell you that most policy makers believe the following: “Yes, there’s a problem of job quantity and quality, but it’s largely a skills problem. Because of recent technological advances, most notably...