I’m not going to defend the self-help industry, but your dismissal made me think of how Craig Ferguson described bad rehabs VS good rehabs.
https://www.youtube.com/watch?v=7ZVWIELHQQY
Yes, of course you need to put in work to enact change. The bigger the change, the more work you need to put in.
That desire for a quick and easy solution to hard problems is exactly what lead to the proliferation of scams.