I don’t understand the brain retraining grifters

There’s a lot of people who built a platform off of claiming to have recovered from ME/CFS (or other chronic illnesses) using brain retraining techniques. My question is, why? Full recovery from ME/CFS isn’t that common and usually it happens completely randomly, so my guess is that either these are people who are still sick and are getting paid to lie about recovery, they had some sort of mental illness that they healed and confused it for a physical issue like ME/CFS, or they were never sick to begin with and just found a community to shill. I’m leaning more towards the last one but again, why? Why is it that the only healthy people who know about ME/CFS are the ones who spread misinformation? What’s is in it for them? They can’t possibly be making THAT much money…