The Great Recession amplified the economic anxieties that Americans experience in good and bad times. It also focused policy and media attention on economic problems that predate the downturn by decades. These long-term issues were “rediscovered” as recent structural problems, such as “secular stagnation” and Thomas Piketty’s r (the return on capital) moving closer to g (the economic growth rate). Income inequality became the defining challenge of our time, even though it had been high and rising during the 1990s boom and the financial crisis lowered it significantly (if temporarily).

But “labor-force dropout” — jobless people giving up on finding work …