Does psychotherapy change with the fashion of the day? It seems to me that it might. We can look back at Freudian analysis and see that Freud himself was a product of his time (a time of sexual repression in Victorian Europe) and the citizens of the culture took it on (perhaps, at first for the novelty of the idea). If we look throughout history and the development of such theories, I think that we can map the changes with the changes in culture. The movements in psychotherapy are good ways to look at the movements' effects on culture and the culture's effect on therapy. I will also be taking into account the chicken or egg factor with each movement.
The first movement in psychotherapy was, of course, Freudian analysis. As mentioned, the people of this time repressed their own sexuality. Freud's theory was, to some extent, an essay not only on sexual repression, but also on general repression and other concurrent psychological concerns. Repressing one's own innate sexuality as well as bad memories (through the "stiff upper lip" doctrine, especially) led to the fame of this theory. One reason, possibly, that this is considered the first movement in psychotherapy is that it is the first time that therapy was named such and operationalized as such. The novelty of therapy was high at this point and critique of it came some time after its inception. This critique originated from within and without. Two of Freud's own proteges broke off to create their successful theories. These include Jung and Adler (there were, of course, many others, including Freud himself). Jung's theory especially seems to have taken advantage of a certain mysticism inherent in those days, concurrent with similar study of mysterious phenomena in science and medicine.
Freud's popularity started to wane as the scientific nature of his theory was questioned. The second wave of therapies started. This wave included the other end of the spectrum from Freudian and Jungian analysis: behaviorism. It ames sense to see this as a direct result of Freud's work. Skinner himself eschewed the quasi-mystical nature of Freud's theories for the purely visible and quantifiable nature of a more behaviorist agenda. Science, at this time, was gaining a more consistent quantified requirement. It follows that psychotherapy, still performed mainly by doctors and/or psychiatrists (with the addition of psychologists) would try to mirror such changes.
The pendulum seems to have swung back, as it does, toward a less quantifiable realm to admit the third movement in psychotherapy: humanistic/existential theories. To some degree, I think we can see that this movement or wave, upon examining the positive and negative factors of the first two, tried to expel some of the very negative portions (namely, the psychosexual fixation of Freud and the strict and neutral stance of behaviorism) and celebrate the positive ones (such as, in Freud's theory, the use of the unconscious, general developmental theory, and patience and feeling in talking to the client and, as in a Skinnerian model, a shorter therapeutic session need and a certain "go with what works" feel), in order to gain some ground and create a more viable and user-friendly theory. I am not sure of this, but i would say that with the modernization of education - which is to say the quasi-requirement of it in today's college society - that many more people were opened up to "high-order" anxieties such as existential depression, anxiety, guilt, and terror. Perhaps there is a less interested viewpoint on the more patient-related or medical model (the "talk down to" model). I think that both of these points really do create the need for a theory that both takes existential crises into account and works with, rather than above, a client.