A few things on this thread ...
First, yes there is a DO on dr. 90210 (see avatar), Will Kirby DO. However, he is not a plastic surgeon ... he's a dermatologist. He went to NOVA, did a year of internal medicine in FL, then big brother, then his derm residency with Western University --> dr 90210.
Second, Dr. Kirby probably seems like a tool sometimes ... but the reality is that the guy is a fantastic businessman. He not only pimps his practice out on the show, which I'm sure is pure gold for business, but he also owns a line of laser tattoo/hair removal clinics which he regularly features on the show. Big bucks. He also has his own line of skin care products, and I'm sure makes good money on all his tv stuff. Last, but not least, he seems to be a good doctor as well, and although he seems to definitely take a business like approach to his practice ... he's doing well.
Third, The reason why I like Dr. Kirby is because he truly shows that there is absolutely no limit or mainstream difference between the MD and the DO. This guy built an empire, and his success really puts the 'are you ashamed to be a DO' and 'Can a DO practice medicine' into perspective.
Lastly, about the money thing ... heres the deal. Cosmetic surgery in Los Angeles is a business that thrives on word of mouth, advertising, and who's in, who's out. Practices thrive or fail (in LA) based on this popularity. Being on a show like this puts business through the roof. People see you on TV and automatically assume you are awesome, operate on celebs, etc etc and your appointment book suddenly fills. This = a ton of money, even though cosmetic surgery has a huge overhead, massive mal practice etc etc. However, I'm sure these guys make a TON off the tv show itself, which gives them the fame that boosts the practice and leads to the creation of products, books, or anything else with their name. This collection of everything is what makes them stinking rich. Trust me, Robert Rey can't live above his means by buying a 5 million dollar mansion in Beverly Hills.
Now, without all the fame cosmetic surgeons in LA still do great, but I doubt most have the lifestyle of the guys that have their practice on a major tv show every week.
-Just as an aside, I read an article that Dr. David Matlock now has a copyright on the term 'laser vaginal rejuvenation', trains other surgeons how to do this procedure, only people who buy the laser from the company that he owns can be trained, and he has opened businesses, is trying to create other tv shows, written books ... etc etc, and now claims he makes 12 million a year.