I think most people do only go for a few sessions or a few months until they get some symptom relief or get pissed at the therapist and then they quit. My suspicion is that this forum isn't a representative sample of people in therapy.

I've been going off and on for years. Sometimes I'm not sure it's all that helpful, but sometimes it is, and I don't get complete symptom relief from medication for my recurrent depression. So I keep going. I do change therapists fairly regularly. It seems like I get stuck with the same one all the time. I've never had a therapist kick me out of therapy. It seems like as long as I keep paying, they'll keep seeing me. I guess I can't blame them. I do think insurance companies try to limit the number of sessions sometimes.