Given that “humans are complex” and “it’s individualized”, would advancements be greater and faster by just allowing clinicians and scientists to just talk things out instead of coming up with “studies” which pretend to be “science” with a low reproducibility rate (and non-publishing on null results)?
You may be looking for qualitative data and reporting which is on the rise!
The term "evidence based" is bandied about all the time because insurance companies don't want to cover treatments that aren't considered standard. The problem is everyone is different on some level, and we often don't have the resources to get to the root of any problems. So treatments that may work extremely effectively for some may be thrown out because they don't work effectively for everyone, and can be contraindicated. Somatic therapists especially have to deal with this. Effective treatments are often outside of the "evidence based" tests, which can be based entirely around showing symptom improvement. This creates a catch-22 where if you lessen the restrictions you get a lot of crackpot providers, where if you keep them tight you keep people from being able to access treatments that may work well for them.
There's also competing models for mental problems and approaches - the psychiatric model is similar to a doctor giving treatment for an illness. They tend to have a belief in biological determinism, IE if a parent had an illness then its likely you will have one too. The Biopsychosocial model is a little bit more holistic around the experiences of people and their physical environment and upbringing. The Trauma model is one I personally ascribe more to which conceptualizes mental health problems as understandable reactions to traumatic events that are conditioned within us.
There are a lot of people who get real relief from outside the mainstream providers, and there are a lot of people for whom the standard providers have not been able to help. I think that is part of why there's so much activity around finding better models right now.