I think you're confusing intrinsic and extrinsic motivations with willingness to work hard. You're ascribing a behaviour to a character trait or ability (a "type of person") that is IMO usually due to work circumstances (i.e. a situation that person finds themselves in, and well placed to exploit with the resources they have).
Working 7 days on extrinsic motivations is soul destroying.
Doing the same on intrinsic motivations is life affirming.
There's also different types of work. Manual labour can be done for long hours - if you're young. Mentally intensive work can be done briefly for long hours, but it rapidly stops working well. If you work is more about connecting people and motivating them, I think it's a bit more scalable, especially if you can feed from the
emotional energy of interaction.
If you're working overtime all the time chasing a carrot on a string, you're wasting your life on a tomorrow that will probably never come.
If being in the moment isn't its own reward, that moment only pays off when you get the reward at the end. If you need to put in too many of those moments, no reward justifies it.
If your work isn't playful, all work and no play makes Jack a dull boy.
The book Drive, by Daniel Pink, does a good job of explaining the differences between intrinsic and extrinsic motivations. I recommend the book regardless, but especially if this topic is intriguing to you.
Working 7 days on extrinsic motivations is soul destroying.
Doing the same on intrinsic motivations is life affirming.
There's also different types of work. Manual labour can be done for long hours - if you're young. Mentally intensive work can be done briefly for long hours, but it rapidly stops working well. If you work is more about connecting people and motivating them, I think it's a bit more scalable, especially if you can feed from the emotional energy of interaction.