The most likely cultural trait responsible for the difference in workweek length between the U.S. and the Netherlands in 2020 is:
The U.S. culture prioritizes capitalism, while the Netherlands’ culture prioritizes health and welfare.
This response highlights the emphasis on work and productivity in the U.S., driven by capitalist values, in contrast to the Netherlands, where there is a strong focus on work-life balance and social welfare, resulting in shorter work hours.