I think Audible works though because of the monthly subscription and the fact people get credits a month in exchange for a book. This credit is purchased at a lot lower cost than paying for the book outright. But it's sold on the basis that people will stay subscribed and thus end up with books they wouldn't of otherwise bought as they are looking for something to spend their credit on this month.

A different model than someone actually knowing the author, waiting for the release and then buying it directly from them. It's essentially free money for author/publisher so they are all rushing to the platform.