I personally don't find the prostitution analogy very accurate, more that therapy is a professional service that is very hit-and-miss. I think the sum of experiences reported on this forum shows just that even though I do believe it is more loaded with negative experiences here than the larger picture. But most people I have ever asked in everyday life about their experiences with therapy tend to say either that it helped just a little, or that it never revealed anything they did not know already. I think the "evidence" published is also usually quite biased because there is no way of really telling how much therapy actually contributed to someone's improvement - people usually do a few things and already ruminate on the nature of the issues when they decide something is not working right and they seek help. Of course talking to someone regularly about our issues can be helpful, we are a social species. But whether a therapist does more than decent, reliable people can provide... that is the very hit-and-miss part. Definitely more chance that it will provide something in cases where the client is very isolated and/or struggles with establishing and maintaining meaningful relationships in everyday life, because the only effort they need to invest to have it is paying and going to appointments. But, as many stories shared here also demonstrate, it can also create excessive and harmful dependency in those cases especially.

As to the dynamic of increasing and then dissipating dependency many people seem to experience in therapy, I am not sure it is specific to therapy at all. Normal close relationships tend to have similar dynamic: much more intense and emotionally engaging in the beginning, then become more routine and habitual and less emotionally clouded. If this is useful to experience in therapy, great. But claiming that it is due to some "magic" training and ability Ts have... blah.