If you strip away the BS, talk therapy is basically a social interaction, though a very strange one. It is not, and never will be, a scientific discipline. Same goes for any social interaction.

Talk therapy will also never be "evidence-based" in the true sense of that concept because as everyone knows the deciding factors appear to be so-called non-specific and unpredictable factors relating to chemistry, expectation, belief, coercion, fear, etc.

It's not possible to control human psychology mechanistically or scientifically and the biz ought to stop suggesting such a thing. It's dishonest and delusional.