I think, considering length of "self-help content", there is spectrum, and in the both ends of such spectrum there is conflict of interests - audience vs authors.

In the first end - short-form content: yt shorts, tiktoks, tweets, ig posts - "authors" have interested to just have more engagement, so we end up with ragebait, fringe ideas, etc - everything for just viewers count go up, the substance doesn't matter at all.

In the other end - "long-form" content: books (usually thick ones), writers for some reason need to fill extra content alongside the substance, some off-topic stuff, I'm not professional writer/editor, but I suppose it's protection from some nitpickers, adding some scientific basis to look more solid (don't know why: author can pick any research that support's book idea, even already debunked), maybe there is requierement from publishers, editors, etc.

The sweet spot here are thin books here, but even that case they cannot help much, because even a therapy sometimes cannot help for someone (heck, there is a real person trying help, not just text with ideas!)