I would speculate there will be no works containing no material generated by artificial intelligence soon. At least it will become a common practice to use a GPT to improve your language, possibly also assist the creative proccess by supplying facts and suggesting creative ideas. Everybody uses spell checkers and thesauri already (some also use grammar checkers like Grammarly), also google things up - this will be increasingly extended/replaced with advanced AIs usage. It is generally considered correct for a writer to hire assisnatnst who would proofread their writings before publishing them or even assist their thought through conversation so I can see no big deal in an AI doing the same job.