I think the core problem of most self-help books is that at best, they're usually an article's worth of knowledge and insight stretched to book length for economic reasons.

To be fair, some people probably do benefit from, or at least enjoy, the history, examples and stories used to pad out the length. But in my career I've had to constantly learn new domains to varying depths at high velocity. A good LLM, properly prompted, can be an amazing self-learning tool. Before LLMs I'd often hire an expert, usually a post-doc or professor to spend 2-3 hours one-on-one answering my questions - and those sessions would move at very high-speed, making the investment worth it. For those who are experienced self-learners, an LLM can deliver 60-70% of that value. And, frankly, extracting the relevant knowledge out of the average self-help book is a vastly easier task than that.