I think the point on expense is for £7.99 I get one book per month on Audible, and on Netflix or Apple Music that are a similar cost, I get access to everything on the system, not just one thing.
Yes, exactly this. If an Audible subscription let me listen to everything/anything, it'd be good value, on the same level as most other subscriptions.
Would you pay for Netflix if the monthly fee only let you watch one movie?
A Readly subscription lets you read all the magazines, not just one. Music subscriptions give you access to all the music.
The Spotify family subscription isn't really relevant - Audible isn't a multi-user membership, is it? If I got Apple Music Family we could all listen to everything.
My library has a free audiobook service where you can borrow a few audiobooks at a time.
So I still think Audible is too expensive for what you get.