I believe therapy is very hard work for both the therapist and the client and I cannot imagine staying in therapy where I didn't think I was benefiting (it's expensive and time consuming too) and if the client isn't working hard, I have heard from therapists that it is very boring or frustrating and I can't imagine being that bored for that long just for a bit of money (from one person).

It sounds like you are assuming there are some therapists who have multiple clients who don't "need" therapy in order to make a little money; I don't think most educated people would want to work at a job that wasn't enjoyable that long? Sit for 50 minutes alone in a room, not able to get up or "do" anything but listen and find a boring person you don't enjoy listening to and have them talk. Could you do that for years with multiple people?