I’ve heard this repeated a lot. I have no doubt this is true for some people (maybe even the majority of people for which therapy doesn’t work, I don’t know). However, I wouldn’t want to claim this is the only reason. Especially since it’s a great effort for many people to even make it to therapy in the first place. They are making an effort. And it’s disheartening to then turn around and tell them they’re the problem if it doesn’t work.