It doesn’t mean they are working.
For example, we hear how many hours the Japanese put in the office, but somebody told me that there is a lot of off time, while at the office. They just don’t spend a lot of time at home.
Work is a way of life in Japan. Homes are too small to hang out.
Israelis hold their own, but yes, if you multiply hours worked times productivity per hour, the US tops them.
Different places are different but in general you're right; NO ONE wants 2b seen by his/her peers are leaving first, or simply leaving before one's subordinates. Soooo many people play around at their desks, pretending to work.
The guy whose super efficient but leaves when he's really DONE? He'll often be tarred as LAZY. The guy doing nothing but consistently leaves last? "Oh, wow, that guy really works his tail off..."
Totally stupid.
It's like stupid law firm games where you go into the office on Saturday for 10 min simply to put hang your blazer on your chair, "Oh, wow, that guy came in to work..!"
Except that most of Japan is doing it.