I'd wager that most people have just their parents to go off of and a few recallibrate using their own experiences, learning, and introspecting about them. Those are the few to whom books and seminars are useful as sources.

I think, for a large number of people, self-help (especially the short form high intensity style content that influencers post is just "content" to "consume" - a form of cheap entertainment that's thrown out almost as soon as it's consumed. There's no enduring change. That takes time and an semi-innate desire to change. Then, all these things become sensible and useful.

I'm not a big fan of Ferris but I'm willing to bet that someone who sits down with one of his books and works through it slowly applying the lessons to his or her own life will see some kind of change as opposed to the typical person who just asks an LLM to summarise the book or a video about it and then decides that they've changed.