The main problem is that so many books are really just essays or papers that get stretched to 300 pages because that is what the publisher wants. A great book I don't think has this problem.
I don't see a separation though between books, LLMs, papers and audiobooks. I would add youtube lectures in there too. They are all valued friends in learning to me.
Second, you’re getting a more compressed and lossy form of that information from an LLM, unless you go to such efforts that it’s be easier to just read the book. It’s akin to a conversation where a friend asks you about a book in finer and finer detail until you either recite the book for them word for word or direct them to just go read the book.
So, I don’t think LLMs are replacements for reading books. They’re complimentary.