Lot of self help content can also be more about feeling good while you're consuming it, than actual lasting change. Even if it's generally good advice. This guy made a video about it https://www.youtube.com/watch?v=dmLTLkCBSN8.

And it's natural to blame the consumers for any failure rather than the material ("you're just doing it wrong", "it's your fault you didn't apply it correctly", etc.), which makes selling mediocre and just plain weak content very easy.