I agree with your conclusion, but what you characterize as therapy is quite a small part of what it is (or can be, there's lots of different kinds.)
Not sure what you refer about "talk therapy" in this case (psychoanalysis, maybe?), as even CBT needs homework and check-ins to be done.
I coild argue that DBT is kind of just a variant of CBT, and while it's generally got evidence of being more effective there's credible sources suggesting CBT is effective (even if it's not quite as good). But nah.
I know there's exceptions. I said there's exceptions.