Yeah, I'm mostly with you.

I do think that most people won't produce more (of the same quality) working 80 hours/wk unless they are exceptionally motivated.

However, with the right motivation, people will. I'm guessing that what that motivation looks like varies from person to person. For me, it's when I'm starting my own venture.

I'm willing to sacrifice to such an extreme degree for that. I cannot imagine any other company being able to come up with sufficient motivation to make it possible for me to work productively 80 hours/week, though. It's not a matter of me being willing to do it, it's a matter that I wouldn't be able to do it.