Thay haven't cast him out, though. He wanted out and so did his wife, so he has left of his own accord. If he left employment in any other organisation he wouldn't be able to use their publicity for his own company. He and Meghan want to have their cake and eat it - all the trappings of being a part of the royal family without the work and inconveniences.
Striking out on their own and being self-supporting brings its own satisfaction - and its own problems, which have to be solved by their oen efforts. That is what the millions who are not born into a hereditary organisation have to face.