My current therapist and I have never spoken about it, but some things he's written have talked about that part of his career trajectory. It seems he didn't initially intend to focus on therapy, but became interested in psychoanalysis during his psychiatry residency. Now that I'm thinking about this, I'm also curious what he'd say if I asked him about it.
I asked a past therapist about this while I was seeing her, and she said she became a therapist because she'd been helped by therapy.