Not to mention that programmers consistently doing 16 hour days would get exhausted and burnt out within a week, making their productivity plummet.

No manager in their right mind would trust code from utterly exhausted people written after midnight to manage billions of dollars of capital.

I met a banking C++ engineer years ago who was the only one left locally and spent his time teaching C++ to fresh offshore engineers in the form of code reviews. He was kind of a manager, though also his manager was probably rational.

1. It makes no correction in how an irrational institution is run that first level managers are rational. It just means they are stressed.

2. I met him at a language meetup for another language, he wanted out but would have trouble making half his salary.

(If you wanted me to trust code written by interns and reviewed across distance and language barriers, C++ wouldn't be my first choice, assuming I got a job in banking management, how likely would it be that I could change anything about that?)

I think it's safe to say that software development drains the brain fairly quickly. We've all slept under our desks a couple times and worked crazy hours for a few weeks, but anything beyond that doesn't sound humane or even possible. I straight up have difficulty conversing with people after those stints. Brain just shuts off. Stare at wall. Then again, there's astronauts and brain surgeons. Apparently trading desks need freaks.