these days a midlevel pulls in almost as much as an internist. So its not that surprising that internists frequently just hire other internists to join them in their group instead of a pa or np. You have to supervise pa's and np's and you are liable for any crazy thing they decide to do with a patient. It makes more sense for people like dermatologist, who make their money doing procedures and who make much more then the midlevel people, to hire someone to field their skin cancer screening and post-biopsy patients rather then highering another dermatologist to do the scut work. ALso, there is a shortage of np's and pa's, one of the reasons their salaries are being driven so highly. So the more highly reimbursed specialties get first picks because they can pay them more.