I believe that change within a person can occur only when that person is willing to accept change. All the therapy in the world, all talking to, all the screw-ups one makes, all the drugs, all their experiences will not force a change on an individual. The bulk of them can add up to all prepare an individual to become ready for change or one of them may finally lead to that moment when a person is truly ready for change.
It must be difficult to be a therapist struggling to help someone change when that person time and again comes in with the same problems. I’m sure it takes patience, but I’m sure at times it could wear down even the most patient of therapists.