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 explanation aligns with the notable difference in average work hours, as the U.S. often emphasizes longer work hours and productivity in a capitalist framework, whereas the Netherlands tends to prioritize work-life balance, health, and welfare considerations, contributing to a shorter workweek.