I do think some Ts are afraid of the intensity. The sheer amount of personal investment and emotional presence demanded of the therapist.
It took me a year to believe she cared and that was because she always was emotionally present no matter how difficult it was - be it traumatic memories or my guarded hostile suspicion or me shaking trembling fear.
Right there in the room with me. She says she believes there can be no deep understanding and thus healing, if the T is not willing to be close and genuine and themself in the therapy space. There's no room for distance, no place for "I'm going to put myself in a bubble seperate untouched".
That doesn't mean there isn't space though. In the beginning before I attached, when I was still prickly, scared, hostile, suspicious, she had to give me a lot of space (so not gushingly warm, I'd have fled!) But she always made it clear that she desired connection with me - to see me, to hear me, to understand me,to meet my needs, to see the needs behind the fear and hostility. Even the hostile wariness.
We joke about it now but it was like a human trying to reach out and pet a terrified porcupine who would bristle quills at the slightest thing.
The stuff in schema therapy books and manuals talks about how the T must care genuinely and deeply for the client for "limited reparenting" to work.
Schema therapy is meant to be long term (compared to 12 sessions CBT) - at least a year just to build trust.
The big study on its use in borderline PD (there's also literature on how it can be used with dissociative disorders) and it talks about 2 sessions per week for 3 years.
Hence yes, I believe only certain types of T would want to work in this modality or other modalities with reparenting as a concept.
I know I'm singing the praises of schema therapy haha. I'm not saying its the cure all for everything -- just my firm belief in the healing power of a genuinely caring T willing to do reparenting aspects.