I don't see how selling a model or the use of a model infringes on a specific copyright. whose copyright has been infringed? how can you prove that? take AI out of the question. if you wanted to prove that some other author has infringed the copyright on your novel, how would you do that? if you want to prove that some quote unquote artist has infringed on your copyright, how would you do that? if any of your methods for proving that a person has infringed on your copyright is applicable to an AI, then that's what that is. but if you can't prove it, if the AI just learned about how style works, if an AI just saw your work but never actually copied it, then it's not infringing.

are you saying that selling a book that has the same characters as a recently released book doing the same things but with wording differences is somehow fair use? Like a book called Harry Potter and the Something Rock with the exact same plot points but worded slightly different is fair use?

no. I was saying selling an AI model or access to it that is capable of producing that work is not, itself, copyright infringement.

in fact, do you know what a clean room is? if I provided to a writing team every English language work except those written by JK Rowling and it produced a work exactly like you're describing, The resultant work would not be infringing copyright. it should not be any different for AI where you cannot prove what materials it was provided.