I think silicon valley is an atypical example compared to the typical workforce. We are presumably talking about the high end of the technological productivity spectrum. And as we know the tails come apart. I'd guess that a lot of special people cluster in these jobs. Sure the tech companies try a lot to make work convenient - but I think a lot of the people working there are at least partly such highly productive because they invested lots of time into technology all their life. Working long ours in your calling is normal.

Look at me: I work 40 'normal' free-lance hours - more is not sustainable with 4 children. But many days I sit behind my PC 4 to 6 extra hours (often in thenight because I need less sleep). These are productive hours mostly. Coding, researching, learning, LW. Also on weekends. If a topic interests me I can keep up flow and concentration 16 hours straight. It is just for my family streak that I don't work insane business hours.

And I guess there are other people our there that are alike. Thus normal workplace lessons don't apply here.