Nathan Schneider asks the question in VICE:

The United States now leads the pack of the wealthiest countries in annual working hours. US workers put in as many as 300 more hours a year than their counterparts in Western Europe, largely thanks to the lack of paid leave. (The Germans work far less than we do, while the Greeks work considerably more.) Average worker productivity has doubled a couple of times since 1950, but income has stagnated—unless you’re just looking at the rich, who’ve become a great deal richer. The value from that extra productivity, after all, has to go somewhere.

It used to be common sense that advances in technology would bring more leisure time. “If every man and woman would work for four hours each day on something useful,” Benjamin Franklin assumed, “that labor would produce sufficient to procure all the necessaries and comforts of life.” Science fiction has tended to consider a future with shorter hours to be all but an axiom. Edward Bellamy’s 1888 best seller Looking Backward describes a year 2000 in which people do their jobs for about four to eight hours, with less attractive tasks requiring less time. In the universe of Star Trek, work is done for personal development, not material necessity.

There was a point in history, Schneider shows, when the trajectory of how much time human beings would spend laboring was on the decline. But capitalism couldn't abide that notion. In the 1930s, the Senate passed a 30-hour workweek, but FDR withdrew his support for the Black-Connery Bill under pressure from industry titans and the measure failed in the House.

One major company, Kellogg, voluntarily implemented a six-hour workday for its Michigan workers in 1930 and hourly productivity soared—until in 1985, during the Reagan era, when the company threatened to relocate unless workers accepted eight-hour shifts. One worker wrote the six-hour shift a tender eulogy:

Tis sad, but true,
Now you’re gone and we’re all so blue!
Get out your vitamins, give the doctor a call,
Cause old eight hours has got us all.

Fascinating stuff. Read the whole VICE piece here.