In order to diversify one's money-making schemes as an author, one must first be making money as an author.
Making money as an author. Haha. Who told you I make money as an author? Perhaps I did at one time. Currently, the cash comes in the door because I picked up a gig as a technical writer. Boring af but it pays the bills. Other than that, all of my effort goes toward trying to get a book written, edited, and out the door in the fragments of time outside of the day job and the demands of family.
Plenty of people in the writing world have made fantastic alternate income streams for themselves. I pay for some of the services offered via those streams. But honestly. I'd like to get back in the swing of being an author and maybe being paid a little bit before contemplating other business opportunities. Maybe I lack imagination, but I do feel like I might ought to nail the titular entrepreneurship effort first.