Humans all across the developed world work 40% fewer hours than in 1900: https://ourworldindata.org/working-more-than-ever. Yet, in the U.S., TFR has consistently been dropping since 1800: https://ourworldindata.org/working-more-than-ever.

> Working hours for the average worker have decreased dramatically over the last 150 years.

note the “average worker”.

If women were staying at home with children, they were not counted as workers.

If they were, the averages would just be higher, their jobs are nonstop at home.