I think it comes down to individual learning style. Here [1] is James Clear tweeting a 3-sentence summary of his book. These ideas totally impacted the way I operate and helped me achieve a lot more than I would have on my own. But I needed to read the book to implement these tactics. If I only read the tweet, I don't think it would have had any long-term impact on me.

I agree that being wordy can be a waste of time! And I agree that many business books blow up small ideas into large books. I also think that sometimes expanding on an impactful insight can help you teach it better.

[1] https://twitter.com/JamesClear/status/1477686252333903877