agree. I'd say it's impossible to solve. Where would we even place our yardsticks:
Has society been able to get any better (than we used to) at assessing and categorizing what "constitutes" great writing? If so in what relation could that be measured to our past performance especially that many no longer read today due to our loss of attention span? (most won't even read this comment because it's way too long).
People are terrible at spotting some of the best writing when it happens. History is full of writers who's work could only be understood and appreciated after their death. Death makes their work a finite commodity. There is no more chance asking the author "what they meant". Others get shunned because they were too radical, (or too ahead of their times).
Great writers as in "a radical new style" or as "for their radical ideas" get only credited after decades (if not centuries) post mortem. When it's too upsetting (because it's true) we need the distance of history and later generations to appreciate it.
Even "what" we comprehend and then appreciate changes over time, and within the same person with every time we read it.
 6 people centuries ahead of their time https://www.oxford-royale.com/articles/6-people-centuries-ah... <- there are hundreds of wrtiers like this (it is just the top result google gave me). How would an AI spot it when all AI was created "in our image". And if it did spot it how would the AI be able to convince us that this is worth a closer look instead that we need to destroy the AI?
 The Last Messiah by Peter Wessel Zapffe https://philosophynow.org/issues/45/The_Last_Messiah <- say something mediocre to ensure you get published and ranked in "best new books". But saying something profound can potentially get you ignored (at best) and killed (at worst). This ties back to
 James Joyce Dubliners https://archive.org/details/dubliners00joycrich / https://en.wikipedia.org/wiki/Dubliners <- there are hundreds of examples like Dubliners but they are all different books depending on who reads them and when. the retrospect and integrating what we read (and then re-read over and over at various stages of our lives) into our own reality is what is makes it great. yet even if some minority of people does practice this, it's still highly subjective. how would an AI provide us with value (e.g. if it can the value it creates would only benefit itself but never others)
I'm not saying AI is incapable of better writing than AI is now, but it would only remain mediocre and never outperform humans. Also the writing can't stand or be judged by itself. It can only be valued and appreciated through human mind. Art (and many books are art) has the same problematic relationship with AI. John Berger's "Ways of seeing" talks about this (but so does a lot of philosophy) https://www.youtube.com/watch?v=0pDE4VX_9Kk
I admit I was going to skip it, but I saw a reference to a James Joyce's book and reconsidered :)