David Goggins is kind of a perfect example of this. There is zero value in an AI-written book that isn't attached directly to his public persona and media presence. Maybe today he can use AI to write the book, but it's still tied to his video media of doing tough challenges, etc. An AI-first author writing such books would get nowhere, as he/she has no credibility.
That all aside, I actually think the most philosophically interesting result of LLMs is that ideas actually end up mattering a lot more than execution. The LLM can't really think for you, and so your knowledge and experiences are actually what matters, as it determines "what you prompt."
In short, the authors that win the future will be ones with robust personal brands and a big social media footprint. The days of the mysterious writer that gets chosen and published by a small group of elites at the publishing house is probably over... at least until the ecosystem becomes so messy that curators become necessary again.