My whole therapy has been focused on my isolation and how to mitigate it. We don't deal with the "why" because 1) my therapist doesn't do "why" very well, which is probably why she's a CBT, 2) we've determined that the ultimate cause of the isolation is neurological rather than psychological, and 3) I personally don't like delving into "why" either. I'm too much of a concrete-thinker and here-and-now type person to let myself to build complicated stories about a rather uneventful life. I understand that it works for others. But it's much too abstract for me.

No, there is no plan for change. My therapist IS the "supportive people" for right now. I don't know how to get other supportive people, which I suppose is the job of therapy. But I also don't want unpaid, free-range, non-professional supportive people (aka friends) in my life. My therapist can't make me want something I don't want. But she's trying to at least get me to not self-isolate so much, and we have been somewhat successful in "putting me out there" more than I used to be.