As someone who has been writing in the self-improvement industry since 2015, this was one aspect that took me a handful of years to realize and I think what you're saying speaks to something underneath that many self-help gurus fail to realize:

People do a lot of talking but not a lot of doing.

Some of them have the charm and have the right set of skills to get away with craftily offering advice that they themselves never took or to take something minor in their lives and make it a really big deal. They never learned what happens when you fail to charm a crowd like that or to get an audience to think that they're just like them.

Because if you did fail, you'd have to actually put effort into improving yourself and recognizing that not every method works and that some of the advice people offer is all bullshit or the person offering it is in a privileged position in the first place and they don't realize it.