But I’m unsure how impactful revenue wise for an author can make or how sustainable is it long term.
Most of the books I see on Unlimited are either older books (there are some good gems), books that are already freely found on the internet or books that are scrappily put together.
On the one hand, there are no 10 hour songs with some great part spread out randomly throughout that listeners have to find (obvious, and I think such a book wouldn't be successful either).
On the other hand there are tons of generated crap on Spotify, than sometimes sneaks into your playlists (even things contained text-to-speech advertisement).
I think all such platforms would need some kind of spam filter functionality and a good rating / statistics system so that quality content could be surfaced.