I’m not concerned by the length of time you have been in therapy. Your diagnosis suggests the need for some time in treatment. I do think you should express your concerns to your therapist and come to an understanding about what to expect.
You may, in fact, be building a relationship that will span years. But more important, you are building a knowledge base about the therapeutic process.
You are correct. There are many things that can result in needing a different therapist. That’s okay. There are many, many qualified therapists in the world. Sometimes it is useful to learn that there are many people who can offer needed help; that we aren’t dependent on one special therapist to continue our work.
Should a transfer become necessary (due to a move or another change in circumstances), your therapist will most likely help you identify a likely therapist who can continue your work. If that isn’t possible, you will interview potential new therapists on your own, with a more sophisticated understanding of what you need than when you first started.
I wish you well.