Most of the difference is explained by the numbers of hours worked, since the GDP in purchase parity per hours worked is within 10 % between US and countries li

Most of the difference is explained by the numbers of hours worked, since the GDP in purchase parity per hours worked is within 10 % between US and countries like France or Germany: see e.g. https://data.oecd.org/lprdty/gdp-per-hour-worked.htm https://data.oecd.org/lprdty/gdp-per-hour-worked.htm. So those countries, implicitly or explicitly, made the choice so substitute income for more leisure. Whether that makes them richer/poorer depends on your perspective.