The Great Recession had a major effect on the labor supply numbers, but over the long haul we can discern some patterns among gender and age groups. Note, first, that if Keynes had been talking just about older people, he would have been closer to the mark, because older people do work much less than they did decades ago. Certainly, they work much less than younger people. According to one estimate, men over the age of 65 spend almost 43 percent more time on recreation than do men of prime working age. Over all, older men spend far more time than younger ones on reading, watching television and taking cruises, among other fun activities. Fewer than 20 percent of men over 65 are in the work force today. We tend to take this for granted, but it’s a radical contrast with 1880, when that figure was about 75 percent.

In short, most older people already enjoy a much better deal than Keynes had predicted for the entire work force. The 1930 Keynes essay “Economic Possibilities for Our Grandchildren” didn’t even mention retirement, perhaps because he was accustomed to a world in which so many people worked until they died or were seriously disabled.

Teenagers are also ahead of Keynes’s workplace predictions. Several decades ago, about 55 percent of teenagers had jobs, but lately only about 35 percent do. In addition, service sector jobs have been replacing jobs involving manual labor. While enormous disparities exist among teenagers of different races and income groups, over all, life has gotten easier for them.

A crucially important cohort is working less, too, though not as little as Keynes expected. In 2014, about 12 percent of American men ages 25 to 54 neither had jobs nor were looking for work, compared with about 8 percent in 1994. With a healthier job market, more of those men would probably be working.

If people in all of these groups are working less, then someone must be working more. The answer, overwhelmingly, is women, who have taken on an Atlaslike role in supporting American economic growth.