I’m not sure you understand the phone book business at all. Any company at any time could have printed a book and sent it to everyone in an area, these competitors that did send a book did not charge people to have the book, they were published and delivered for free.
And who paid to print and distribute them? In the case of the phone company with the monopoly, it was the customers. In the business world, they call that an advantage. When it is the result of a government mandated monopoly, its called a racket.