It’s a business fact that if you have a product that is known to sell, you can find salespeople willing to sell it on commission. A new book by an unknown author has no such track record. Book marketers are not willing to work on commission when they have no reason to believe that their efforts will result in enough sales to be worth their time. That is why they want to be paid up front. Regardless of results.
Traditional publishers know this. They sell books first and then pay the author royalties based on book sales. Any advances given by the publisher are paid back by the author from royalties earned by the author. Publishers keep their eye on their R.O.I. -return on investment.
The Internet sparkles with schemes -er, sorry- ways for an author to sell their books. None of them, to my knowledge, work on commission. None of them work at all. Am I wrong? Has any author paid for book marketing and received a return on their investment? I’d love to know, and I’m pretty sure I’m not alone.