I do not believe this narrative that is only confirmed by billionaires themselves. They mostly rely on the work in others for their success, why working more hours would even have an impact?
Example: An accountant who works 8h/d does very taxing, mental work. They require high concentration and precision, it’s often quite boring stuff, but still, they have to get things right, quickly, constantly.
A manager or director might effectively work more hours, but those hours typically have a much more natural rhythm to them. The vast majority of it is communication or preparing for such. The hard part is making the right decisions, listening learning (broad sense), but it’s not detailed and constant.
We programmers tend to complain when we have too many meetings and purely conceptual/communicative work, because it doesn’t „feel“ like work and getting things done, right? There’s a hint there.
For me, 3-4h of highly concentrated programming and testing is much more taxing than a full day of communication/learning. Much more.
Interesting example with the accountant: constant precision required, although monotonous. Not easy