There’s two types of people: those that do as much on their own as possible because maybe they struggle with delegation or maybe they simply can’t afford to delegate. And then there are those who try to pass off as much as they can to be free to focus on what they love to do and on what they are best at.
When it comes to business, you have to make money in order to hire others to do those extra jobs. And so, see also John Gruber’s article from 2009, Obsession Times Voice, where he aptly quotes Walt Disney:
We don’t make movies to make money, we make money to make more movies.