Sounds like an interesting book but the article says remarkably little.
Just like how human beings choose different ways of presenting themselves to the world (e.g. masculine/feminine, gay/straight, goth/punk/preppy) as a form of social signaling, today's LLMs emit a certain "I'm AI" signal that humans pick up on, and human writers will likely have to continue evolving the counter-position(s) to that signal.
If the results of relatively simple, unsophisticated prompts get better at passing for human-written articles/blog posts/forum comments/etc, that'll increase the fraction of human writing that falls into this uncanny valley, and exacerbate the need for stronger counter-positioning over time.