I'd imagine one of the largest reasons if not the largest would be the lack of vacation days, which the article doesn't even mention.
https://www.theguardian.com/world/2015/feb/22/japan-long-hou...
I think you're counting in the numerous official national holidays, but those are so sparse, and the GW is cutthroat to go anywhere.
Then you've been very fortunate. This is not representative of many people - ask anyone working in a restaurant or retail how much paid vacation they get.
Unlike many countries, in the USA the legal minimum is zero.
plus this is HN, so "every company I've ever worked for" is almost certainly a white collar STEM gig -- which ain't 90% of the country.
High pressure not to take it? I doubt you can say that with any level of confidence.
These are both also untrue based on my experience.