I wouldn't diss primary care. Aside from supply and demand, there's another economic truism in life:
Whoever sees the money first or is the one shaking the hand in each major business transaction, makes the most money.
In medicine, that would mean the PCPs, first line specialists like derm and the surgeons. In the business world, they would be known as the "front office" or the revenue generators. Of course the insurance and management guys see the money even earlier.
Fee for service ironically is what has kept the cost-side "back office" medical specialties such as anesthesia, radiology, rad onc and path in the running for so long. The eventual retirement of fee for service in favor of ACOs is going to crush these specialties, because the money pool is going to first go through the PCPs and surgeons (they bring in the patients). The administrators will always in time kiss ass to the real revenue generators. With fee for service, it didn't matter as long as your code paid a defined amount, but if you get rid of fee for service, watch out because the truism will come back to play.