Most, if not all, primary care functions can be performed just as well by nurse practitioners, physician assistants, or other types of providers, especially if you allow for additional postgraduate training.

There are three basic ways the AMA cartel hurts healthcare:

1. First, as others have pointed out, there is an significant artificial restriction in supply of physicians. Many more people could be admitted to medical school, successfully finish training, and practice well than there are now.

2. There's an artificial restriction in the supply of providers, and more deeply, an artificial restriction in the schema we have about who we get services from and how they're trained. The AMA uses FUD to reinforce a model where the only appropriate training model is undergraduate -> MD -> residency -> post residency, and because almost everything pertaining to well-being is health, those who have undergone that training model supercede others regardless of training history.

At least in the US, we don't really question this assumption at all, even though there's no evidence it's superior to a different model that has different routes, like undergraduate -> specialty training -> broadening of training, or undergraduate -> broad non MD medical training -> additional training. Mix and match however you want. Whenever other provider types have broadened their training (dentists, psychologists, optometrists, etc.) there has always been pushback from the AMA, and the scientific evidence has never supported that pushback. So why not allow LPNs, PAs, pharmacists, optometrists, dentists, psychologists, audiologists, etc. to broaden their scope of practice, with the appropriate background and training?

The insistence on the undergrad -> MD -> residency model becomes even more absurd when you consider how brief MD training programs are becoming. It's not uncommon for them to only have 2 or even 1.5 years of academic coursework, with the rest clinical training, so how is that actually different from, say, a PA with additional years of experience in practice? Especially when you consider PA programs often require more medical experience before entering than medical school entrants -- it's all 1.5-2 years of coursework plus years of hands-on supervised clinical training.

3. This cartel actually hurts physicians as well, by increasing their workloads to impossible extents, and by creating artificial restrictions in specialty certification. This gets a lot less attention and is maybe harder to explain, but the licensure and specialty certification requirements are also getting more and more absurd, to the point that in many specialties they no longer realistically reflect actual skill, and are simply ways to further increase the rent-seeking advantages within medicine, and to line the pockets of the AMA and specialty organizations.

Practice and provider regulations, in my opinion, are one of the major drivers of healthcare costs in the US, and it almost never gets any discussion, because it's immediately shutdown. The argument is "if you in any way increase the supply of providers providing care, under any other model than an MD, people will get hurt."

I say this as someone who has worked in healthcare and has many immediate family working in healthcare, in a variety of roles, from nurses, to physicians, to other professional roles.

(See also: opioid crisis and cannabis regulation for how well our current regulatory system is working.)