You (the ostensible writer or publisher) have to lie forever for me to continue reading your content in this case. Immediately it comes out that any of the writing from an author/outlet is AI generated, I will blacklist them from my reading list forever. The point of reading (to me) is to commune with fellow humans and learn from their lived experience, it's not just to consume prose.
It's not the most enticing thing. If the prompt is nicely crafted, you get more intentional results, and maybe that's interesting. Seems a tough sell. I suppose there are authors like Simenon and Pratchett who would churn out books at the rate of at least one a year, and fans might wish for increased output, so maybe there's a niche for a slop-assisted author.
I tend to agree but, for the sake of argument: what if you don't know?
It seems most people who say they can tell, actually can't.