I've had many posts on the Autor and Dorn paper on the hollowing out of the middle class (see here too), and this is yet another, but let me add one thing. This explains the demise of the middle class as a result of technological change. However, there are those who argue that the troubles of the working class has happened for other reasons, e.g. the demise of unions as politicians favored business over labor, or that there have been other political/institutional changes that worked against the middle class. My own view is that it wasn't one or the other, both technology and politics mattered:
How Technology Wrecks the Middle Class, by David Autor and David Dorn, Commentary, NY Times: In the four years since the Great Recession officially ended, the productivity of American workers — those lucky enough to have jobs — has risen smartly. But the United States still has two million fewer jobs than before the downturn, the unemployment rate is stuck at levels not seen since the early 1990s and the proportion of adults who are working is four percentage points off its peak in 2000.
This job drought has spurred pundits to wonder whether a profound employment sickness has overtaken us. And from there, it’s only a short leap to ask whether that illness isn’t productivity itself. Have we mechanized and computerized ourselves into obsolescence?
Are we in danger of losing the “race against the machine,” as the M.I.T. scholars Erik Brynjolfsson and Andrew McAfee argue in a recent book? Are we becoming enslaved to our “robot overlords,” as the journalist Kevin Drum warned in Mother Jones? Do “smart machines” threaten us with “long-term misery,” as the economists Jeffrey D. Sachs and Laurence J. Kotlikoff prophesied earlier this year? Have we reached “the end of labor,” as Noah Smith laments in The Atlantic? ...