I've already seen people generate images for their RPG campaigns using Stable Diffusion, how many rule/campaign books will a LLM need to crunch through before it can spit out endless variations on a theme for your favorite system (or act as a major accelerator for those creating them already)

Edit: actually lets expand on this.

What happens when a sufficiently advanced model gets licensed for fine tune to paying companies and Wizards of the Coast feeds in the entire corpus of data they control and starts using that to create or help create expansions and systems and the former creators shift to editors.

Now do that for every industry that has a text backbone somewhere in it. e.g. movie/tv scripts, books, comics, radio dramas, music video concepts, and so on.