You are right, its definitely a leadership issue, if you have really hired the right lieutenants and 100% trust them, you don't need to be pulling 70 hr weeks. Unfortunately, most "leaders" never allow that, they love to get involved in every fire - big or small, and I feel, they derive their sense of self-worth from it.
You know the romantic arc in some comedies and many action movies? The people in a stressful situation form a bond. At the beginning they hated each other. At the end they were living happily ever after.
It's not just a movie trope, it's a human cliche. Pour enough oxytocin onto a human brain and you'll believe anybody is your bestie. Survival creates a bond.
These guys create emergencies and then become emotionally invested in the heroes who show up and fix the problem. If they do that repeatedly, the bond is stronger. Infuriatingly, that often holds for people fixing the same problem over and over. They want to keep these 'friends' around and ignore everyone else.
They have no emotional bond for most of the people who would let them go home after 40 or 50 hours.
I've definitely seen that, it morphs into a bro-code of sorts. Interestingly, most of corporate America borrows its parlance from the military ( pick your battles, rally the troops..)
Someone, thought up this psycho-babble to make corporate jobs sound and mean as important as being at war.
The good ones either could do, or at least verbalize how they wished their bosses would do, some pretty effective delegation by... well... leading.
There are ways to communicate the overall picture and the goals of a project so that people generally know what is expected of them, and feel empowered to go and tackle individual problems that lie in the way. Even if they don't act, it's no surprise to them when their performance review is bad because they knew what everyone was doing and they chose not to participate.
Nobody is being micromanaged, nobody is working on 'pointless' stuff. Everybody can and most people do step up.
There's a weird bit of human psychology that can be used cynically (as by con men and serial killers), but it doesn't have to be: If you trust people, they are inclined to trust you. I think that may be part of the dynamic that goes on in these situations. Here's my dream, I'm sharing it with you, let's go do it.
I wonder if we should be focusing a lot harder on communication skills and leadership training. Because if you can wind up that toy and walk away from it, do you really need to be working 70 hours a week? Or do you have people for that?