As an Audible customer, I don't really mind this. Unless you're listening to a book read by the author or a Sci-Fi audiobook with multiple actors voicing characters, I already have zero loyalty to narrators.
The Audible/Kindle ecosystems already had more garbage than any human could consume that AI-generated stuff won't make a big difference.
As a human professional, it does pain me to see another profession automated away.
Loads of this sort on youtube stories. It has many flaws in pace and emphasis as well as run togethers of 2 sentences. IDK if a missed full stop = period in USA created the run together. That said it is easily seen. One hopes correct spelling. Best would be a scripting person runs through it first - he said/she said step? Maybe an AI scripter = first run to reduce the AI stumbles.
Audible is well aware of this aspect and I would expect a good product.
There are a number of online narrators that 'read' asci = OK for a book while you workout/run - but has the same problems