I'm a doctor working in the UK, a few points.
1) As Carl notes, Medical wages in the US are particularly extravagant, but they are still pretty high in other places in the anglophone world, and high generally. Carl has done more research on this than me, but moving to practice in the US has significant transaction costs, which may make moving not-that-great on expectation. In summary, the short- and medium- term changes in medical reimbursement in the US shouldn't be a dominant consideration.
2) It is not clear to what degree medical wages are inflated. Ex ante, you'd be surprised if the optimal model of healthcare was designed around an elite corpus of highly skilled people people (doctors) in charge of almost all aspects of patient care, and involved in almost every interaction a patient has with the system. Corrections to that (in terms of increasing automation, division of labour with easier tasks handed off to lower-skilled staff) seem to be brewing in most healthcare systems, and may have a downward effect on wages. There's also the effect of immigration reform exerting further downward pressure on wages if the medical guild's protectionism can be broken. These may also give opportunities for leveraging these things, leading to possible increased variance in returns on medical careers (the 'job for life' model where everyone becomes a consultant/specialist of approximately similar rank may go, with 'superstars' presiding over more junior staff).
That being said, it isn't clear whether doctors are a poor value proposition at the moment: some very speculative research I've done on the marginal health impact of additional doctors puts their 'cost per QALY' in line with marginal health technology expenditure, at least in the UK. Also, being a doctor is demanding across a variety of axes (intelligence, domain knowledge, social interaction), so they are more robust to disruption than most other jobs. So I doubt any dramatic change in salaries for doctors in the developed world anytime soon, but I'd predict they will go down rather than up.
3) Medical schools effectively select for intelligence, conscientiousness, integrity/appropriate behavior, social skills, and dedication to the profession. Due to competitiveness, medical schools can select far from the right tail. I'd guess there are better good opportunities in other EtG paths than medicine for any given level of ability, especially given the high upfront costs.
The cases where I think it would most likely be an optimal fit are for people who are 2ishSD above the mean in IQ, very conscientious, and good (but not exceptional) 'soft skills': you are smart and hardworking enough to have a good shot at medical school, but you aren't smart enough where you have a good chance of 'winning big' at a g-loaded tournament game (start-ups, finance, STEM), and you aren't socially good enough to win big at socially loaded tournament-games like business/entrepreneurship either.
4) The 'soft factors' are important for getting through medical school and staying in the job. You spend your time learning to memorize and apply large amounts of factual data. On the job, you need to be able to interact well with patients and colleagues from all backgrounds, you need to cope with episodes of high physical and emotional stress (examples from my first month of being a doctor: telling a patient they were going to die, telling a relative we were stopping active treatment of her husband for 60 years, being the first responder to a patient who had thrown up a liter of blood and was still doing so, CPR with relatives in the room screaming, trying to talk an extremely agitated person in alcohol withdrawal to let you give them drugs before they go into a life-threatening seizure, lots of seeing and examining dead bodies, body fluids, and body parts); you also need some threshold level of manual dexterity to perform basic procedures like taking blood etc. There are lots of upsides to being a doctor - I really enjoy it - but I think there are lots of people who would struggle despite being smart, hard working, and genuinely invested in their patient's wellbeing.
5) There are fair exit opportunities for medicine (Pharma, consulting, finance), so you aren't 'locked in' to a medical career.
telling a patient they were going to die, telling a relative we were stopping active treatment of her husband for 60 years, being the first responder to a patient who had thrown up a liter of blood and was still doing so, CPR with relatives in the room screaming, trying to talk an extremely agitated person in alcohol withdrawal to let you give them drugs before they go into a life-threatening seizure, lots of seeing and examining dead bodies, body fluids, and body parts)
One of the coolest parts of the job is realizing you've learned to be calm in these situations.
A friend of mine who may want to Earn to Give for the purposes of effective altruism mused 'The wages of American doctors seem inflated right now. I wonder if it is likely that the American health care system will be fixed by the time I am able to work there. If I do go to med school that is.'
Right now, he is an undergraduate student from, and living in, Canada. He is about half-way through a degree in computer science, but he is taking some biology electives. There is a good chance he will switch his major completely to biology, because he no longer believes he wants to become a programmer, and because he is very passionate biology and the study of life, and he would rather go into grad school for biology, or maybe medical school. If he already completed several credits from a previous major, and by December will have done 2 semesters worth of biology classes, I expect it will take him at least another 3 semesters to complete his degree, and/or complete the prerequisites for medical school. If he gets into medical school 2 years from now, it will take him another 4 years of medical-school+residency to be able to practice in the United States, and 2-3 years more than that if he specializes, or goes to a medical school in the Caribbean (where getting into them is apparently easier than mainland medical schools, but to complete the training takes six years). So, it would be at least 6-8 years from now before he is a practicing doctor in the United States.
So, does anyone have any ideas of how to go about the solving the initial problem? What is the likelihood that the wages of American doctors will deflate in the next 6-8 years due to major shifts in how the American medical system is run? What sorts of changes ought one be looking for to answer this question: political, bureaucratic, technological, or cultural change?
edit: my friend in question has expressed interest in this thread, so if you want to make recommendations about or discuss medical schools in the United States vs. other places, or in general, or about entering the medical profession vs.s other jobs, go ahead. Such valuable information would be appreciated. I don't yet know if he himself will participate in this discussion.