In the foreseeable future, I do not see AI creating a coherent novel or even a short story. I find that people typically overestimate the capabilities of computers and underestimate the complexity of human skillsets.
The understanding of how a novel is created is borderline mysticism. Go through a set of creative writing texts and one finds references to muses, the subconscious, left brain-right brain interaction. Ideas percolate up out of the unknown. It is easy to find descriptions of how plot lines should unfold, each of them different and each of them critiqued and rejected. In addition to plot, there are character arcs; the character must grow throughout the story, yet a great deal of popular characters show absolutely no growth. And in setting descriptions, there is the helpful advice of not having 'white room' settings and, when describing the setting, one should avoid 'purple prose.' Maybe one should strive for lavender environments.
Despite mankind's inability to define what a 'good' story entails or how it is created, there is a belief that the computer will discover the master pattern for stories. And to do this, AIs are 'trained' by ingesting the Internet, without any sort of qualifications or analysis. Instead of coherent patterns and story arcs, the result is an amalgamation of ideas and text that quickly shows inconsistencies. Furthermore, the generated text soon reflects some of the worst of ideas rather than being anything uplifting. Mankind does not know how to train an AI to write. It is even challenging to provide a curated list of 'good' writing--remember romance is by far the top selling genre. And there is certainly no known way to teach analysis of any provided text to identify what is good and what is bad. It is simply hoped that AI will make unknown leaps and bounds in analysis and be able to generate the ultimate novel.
I've been involved with computer software development for forty years and, in that time, AI has always been just a few years away. Some aspect of so-called AI will pop up and capture the general public's attention with associated gnashing of teeth over computers soon replacing us all. Then nothing significant happens and all is forgotten for another period of time. Revisit this thread in one year, and I predict the current set of AI programs will have been forgotten and gone the way of NFT hype.