Apparently cosmetic dermatology is not regulated so you can go through residency in some other residency program and set up your shingle selling Botox, at least where I live.
How many people who get into surgery would still do it with all the same education, testing, training, and licensure requirements if it paid $100k/yr? My guess is not many. If you're in a highly litigious state in a high-risk specialty your malpractice insurance alone could be more than that.
It's not surprising to see smart people leave risky positions with pretty objectively bad work-life balance for more money, less stress, and better WLB.