You literally used this as an argument.
Also, I don't think the problem is how much Musk works. If you ask me at the CEO level working "so hard" shows you don't really understand basic delegation techniques. He does work really hard to project the image he's working hard - I'll give you that.
Also, no matter how hard you work you will never make billions off solely just your work. Ain't gonna happen. At some point you need to start exploiting people.