What I bolded is exactly what was driving my pretty long transference pattern in my youth. Not so much in therapy in my early 40s as I never saw the Ts as a more ideal version of me, but there were many people earlier and usually the focus was on specific features with each. For me, the fantasy/idealization wasn't painful but rather inspirational, I used it to try to realize those things in myself, so I only "needed" each person transiently as it was really mostly about myself and my potential and development. And this latter is exactly why, I think, it would be so important in therapy to focus on improving the client's everyday life and outside of therapy satisfaction, rather than focusing on the attachment to the T (a projected, fantasy self-image) but without doing anything to make it real in ourselves. At least for those that experience this type of transference pattern. One can analyze the relationship and attachment to death even with the most competent T, but it will remain frustrating and painful as the gap between who we want to become and who we currently are never gets any narrower, let alone disappear - so the transference is never resolved in a deep, individual sense.

I really think that conventional theories often dismiss the above element of personal development and can distort the meaning of transference, assigning it to old lacks in appropriate parental care and longing for that in therapy. Even if that is true for a person, I think the interpretation is often not deep enough. Why do we need a good parent after all? An important factor is that they can inspire us and help us to strive as individuals and to develop our potentials later in life, as independent, self actualizing people. But if it gets stuck in the relationship and attachment, then such individuation cannot occur, we may continue longing for what feels missing and not realize it is our own, autonomous, accomplished adult self.