I really don't want to defend Amazon's practices on this, but > Amazon is paying for hosting an audio file, basically, and the development of the player app, a

I really don't want to defend Amazon's practices on this, but > Amazon is paying for hosting an audio file, basically, and the development of the player app, and that's it. "development of the player app" is kind of load-bearing in that sentence: They host a directory of books and provide recommendations (which amounts to lead-gen, probably (?) increasing the number of copies of your book that sell because users stumble upon it either by browsing or by searching for keywords). They take payments (not a high bar, but that's 1-3% if you wanted to do it "yourself", not to mention the cost of either integrating with a payment provider yourself or paying somebody to do it, so it shouldn't be forgotten about). Finally, their model where you pay a subscription that gets you a credit per month or whatever leads to even more book sales. I hate this model and I finally ejected myself from the Audible ecosystem, but before I did I spent a bunch of credits that I had saved up.