Self-help is 1 part information and 1 part magnetic point-of-view.
AI is better at personalized information, short-form content offers a snappier and more "real" point-of-view.
What I find most interesting is the appeal to authority aspect. Self-help always has had its gurus. If self-help is getting hit harder than other genres, I wonder what that says about brand trust.
EDIT: could also be that these books are kinda fads. I would expect them to have a shelf-life.