I've often wondered about this. It would seem, once you've established the practice and have the experience, that you could become a part time attorney fairly easily.
I've considered going into estate and financial planning, get things going for ten years or so, then go draw things down, maybe write books or articles (maybe a podcast), and travel a lot. Otoh, could do similar with labor law, but honestly I'm not loving the field. But like most 40yo's, I'm in a somewhat comfortable place and not sure I want to stir #### up right now.