There are several issues at play here that I think need to be disentangled seeing as I'm someone that cares deeply about writing and books.

First, there is the question of the mythology of the author. Would Shakespeare be himself if he had an AI ghost write his books? Would we care as much?

Setting that aside there's nothing to say that an AI will come up with something wholly novel that's not a pastiche of what's come before. Would it be able to come up with the next Dracula? Or the next meme genre of your particular favorite? What about writing style? It could mimic Clarice Lispector but it couldn't create a new one of her. If it did so we wouldn't recognize it as something human that we would be forced to care about in some way. IF an AI came up with a Lispector and we hadn't seen a type of her before perhaps we would think that the machine is hallucinating.

More than that though, why should I buy a book that an AI wrote? I can just ask an AI to tell me a story. Or I can read all of the books that were written pre 2000 - there are more than enough to satisfy my curiosity and desire for enlightenment before machines were used to print money for those that have access to them. For me that's the most galling - it shows that the people that have access to money and the means to make a machine do the thinking for them are unable to come up with an original idea, excepting insofar as they push a button or give a prompt. In a few years when AI achieves consciousness, which I believe it will, we'll be able to have machines that can write their own novels if we wish and they want to do so. Then we can judge them by it's own merits. In the meantime if the person writing the book doesn't have anything interesting to say and isn't an intelligent person and wants to send me a dead tree with information inside it that a machine wrote, what's the value added other than me taking a picture of the blurb on the back and feeding it into an AI and having that AI recreate the book? The paper it's printed on?

EDIT - where AI (not AGI) is important is in doing the sort of hard combinatorial analysis that is so difficult in diffuse systems like traffic control and industrial control of city services or combining chemical and biological synthesis for drug research such as protein folding. AI as a tool for art is one thing, but having an AI create your doctoral dissertation or come up with a book is another. If you can ask an AI to find a cure for a disease or a novel drug and it tells you how step by step by all means do it because it would be absurd not to. It doesn't prove how intelligent you are in that field however - there probably should be altered qualifications for how we rank how useful people are in society given AI prompts and there will be over time unless society just devolves into a "whoever has the most compute wins" dystopia. In which case I'm going back to Plato and Jules Verne.