Some of the best books on JS which were online went recently off-line for that reason. Blog post by the author: https://2ality.com/ (Dr. Axel Rauschmayer)

I read the blog post. It is interesting to me. First, a dumb question: Does putting your website behind a Cloudflare "human tester thingy" help prevent this situation? If not, continue reading. Let's construct a parallel universe. Suppose AI/LLM scaped all JavaScript content except his website(s). Would the outcome look different? I doubt it. In the end, technical books are dead. They will be replaced with AI/LLMs. Even Stack Overflow (which I started using in 2010) effectively killed my need to buy expensive technical books from O'Reilly. And AI/LLMs basically killed Stack Overflow.

This makes me indescribably sad. Dr. Rauschmayer's books and articles helped me tremendously early in my career. I owe him a debt of gratitude.