Why is it that Europeans (on average) work fewer hours than their American counterparts?

I realize that they work less hours each week and that they they have more vacation days.

That’s not what I’m asking about.

I’m wondering how/why it came to be that way. Apparently, in the 1960’s Europeans and Americans worked about the same number of hours each year, on average. Since then, the relative number of hours worked by Europeans has gone down.

Is it a cultural thing? Do they have stronger workers’ unions? Is it due to some technological advances? Is it something else entirely?

I started wondering about it because I came across this quote from economist Olivier Blanchard:

“The main difference between the continents is that Europe has used some of the increase in productivity to increase leisure rather than income, while the U.S. has done the opposite.”

Do you think he’s right?