This isn't an absolute. Of course you can do "sprints" successfully. You just can't do it for very long. And we don't know and never will if one or the other problem they had might not have been prevented if the guy designing or making the part had had enough sleep - so it's always a discussion with insufficient data. After all, we've had enough research to show that a lack of sleep impacts the brain, from psychological studies to neuroscience, which now tells us that the brain is actually cleared of toxins during sleep. For the cases who still get enough sleep, well, not sure how the lack of "a live (outside work)" impacts various factors short and long term.

For my coding work I have stopped doing certain kinds of coding after evening, basically, anything that isn't "mechanic" but requires design decisions. Even if it's "urgent". Executing what I had decided earlier is okay, but decision making just doesn't work as well for me that late in the day, even if I still feel great. The next morning always seems to bring a fresh perspective.

Maybe I've seen it in the past but I don't remember it now -- what is their employee turnover rate? I imagine they have no shortage of applicants willing to put in 70 hour weeks until they burn out, just to get that name on their CV.

This sort of thing makes it hard for me to respect Elon Musk. He is, personally, doing great things, but I wonder if his overall effect on the world is negative in the long term because he's promoting some views that I find very harmful. So many people around him, who admire him, yet he feels like a one man team.

Fun fact -- I originally wrote "80 hour weeks" in my post and thought, "Nah, that's too much," and bumped it down to 70. Looks like I was way off, haha.

Maybe with a less stress, fewer hours culture they would have even more success in the long run. But how can we know that? I think we need leaders willing to take this kind of risk at their companies. Because the outcomes could really change the world.

SpaceX is not your typical company - it's a vehicle created to instantiate an idea (getting humans to Mars and beyond), and not a specialized instance of a generic Company class with a Product parameter set to Rockets. That is, people who work there are the ones who believe in the idea; for them it's more of a vocation, a life itself. Those who don't fit that bill burn out pretty quickly - hence the turnover rate.