The point of CBT isn't that it's going to fix your thinking in a couple of months. Your brain has been wired a certain way for perhaps decades in a certain way. To undo this, takes a lot more than a few months or even a year or two. Also it must be done in combination with multitude of other things such as lifestyle changes, exercise, diet etc etc you already know this.
Also, sometimes you might actually be dealing with real problems in your life, and in that case you need more than just CBT, and actually develop better problem-solving skills. Majority of CBT work and these other skills can only be done outside of therapy sessions. Think about it. You're only in therapy for perhaps an hour or two every week (in general), outside of that how many waking hours are you by yourself or dealing with others? You're GOING to mess up, you're GOING to back track about 10000x times. It's a PROCESS, not a FIX.
I have done CBT for a while, when I was diagnosed with MDD, but later on they found out I also had PTSD, which requires some other types of therapies and techniques too. But I wasn't ready to deal with the trauma because I still lived with my abuser at home.
Also another type of therapy you might want to try is called DBT (Dialectical behavior therapy), and meditation directed by a guide/therapist.
I've also heard LSD and mushrooms can rewire your brain, when done properly with an experienced guide. (There are clinics in the US for this).