I really find this topic interesting so I am writing again. In thinking about why therapist use eclectic appraoaches, I think that was your original quesstion, I remembered reading in a text book that there was a growing awareness in the psychological profession that no one approach to therapy has been able to be completely applicable to all clinical cases. Knowing this, the reasoning would be that therapist after initiating a relationship with the client and gathering information about the clients problem- right there from the begining the therapist should be able to formulate an intervention, a form of therapy that best suits the clients problems. At this initial stage the therapist would integrate the necessary components of approaches.