Why would it come back? I don’t think any research has ever shown that working those kind of hours in “knowledge work” is sustainable or conducive to high produ

Why would it come back? I don’t think any research has ever shown that working those kind of hours in “knowledge work” is sustainable or conducive to high productivity long-term. I expect the “replaceability” that you mention isn’t just “work long and hard or somebody else will”, but also “work long and hard, because you can be easily replaced as soon as you have a breakdown”…