This. I think what people most misunderstand about this kind of environment is that the hours are merely the side product, not the main focus. It is very hard to plan that I will put in 16 hour days. But when it happens naturally, it seems like the easiest thing on the planet(and much easier than not doing it). To get to that position, a lot of fuzzy things align(like the clarity of vision, the challenge, the opportunity etc.)

What is also not said is that most manic types also take more extreme vacations. They might take a week off every few months and completely disappear to recharge themselves.