The countries above the US in their PPP GDPPP/hour worked chart are pretty small ones, more like the size of a US state than USA the country. A US state sized entity can get pretty good returns by focusing on a specialized niche: Massachusetts (larger population than Norway) for example can focus on a sort healthcare/education/biomed cluster and end up with a GDPPP somewhere around 20% higher than the country as a whole.
Luxembourg could be compared to Boston or Seattle or something.
Luxembourg could be compared to Boston or Seattle or something.