This is not an "American" thing, its a high-achiever thing. Valve is known for hiring some of the best people out there. This manual is written specifically for those people and appeals to those people and their values. Keeping those people happy and not looking for new jobs is 90% of what management does. Pretty much any competitive market has attitudes like this. Its just worse/better at certain employers. Considering how fast tech moves, it might not be entirely feasible to stop learning and expect to be competitive in the long run.
Personally, I really don't know anyone with this extreme mindset and work cultures in places like Korea and Japan make the US look like a walk in the park. I think you're overstating the case here more than a little. Its just rhetoric. If anything shops like Valve has all sorts of perks that most offices don't. I think there's a bit "feeding of the ego" with these materials here. Their engineers are good but they're normal people with kids and families and such. They aren't literally "optimizing themselves 24/7." They just like their assess kissed once in a while for staying current and competitive. Being told you're amazing during the on-boarding process is pretty common.
Personally, I really don't know anyone with this extreme mindset and work cultures in places like Korea and Japan make the US look like a walk in the park. I think you're overstating the case here more than a little. Its just rhetoric. If anything shops like Valve has all sorts of perks that most offices don't. I think there's a bit "feeding of the ego" with these materials here. Their engineers are good but they're normal people with kids and families and such. They aren't literally "optimizing themselves 24/7." They just like their assess kissed once in a while for staying current and competitive. Being told you're amazing during the on-boarding process is pretty common.