I'm about as specialized a physician as you can be; I'm a surgical oncologist who has spent the past 25 years running a melanoma and soft tissue oncology program. So, yes, me and my peers around the country (USA) are the ones you want to see if you are diagnosed with advanced melanoma or soft tissue sarcomas. However, the reason I've been able to specialize the way I have is that I worked for a university as a professor and was paid a salary. It would be financially impossible to do what I do as a private practitioner as the operations I perform aren't reimbursed well by insurance companies and your malpractice insurance would be through the roof. Furthermore, at the height of my career I was making approximately 1/2 as much money as my colleagues in private practice. I'm not complaining as I also had an active NCI-funded research laboratory and was able to teach medical students and residents every day. As the saying goes, "If you love what you do you'll never work a day in your life."
90% of oncology care is carried out by private practice physicians in this country and they do an outstanding job treating some of the sickest patients in the world. What is needed is the correct balance - a well trained and dedicated cohort of private physicians that do most of the work, and a much smaller cohort of extreme specialists to whom our private colleagues can send the rare patient that requires our expertise.