Right now, we as a nation have bigger fish to fry - such as making the moral decision on whether we as a society feel healthcare should be a right or a privilege, and getting the right alignment between economic incentives and effective healthcare.
Your larger points may hold but I think you're underestimating the need for more physicians in the future.
There's firstly the obvious aging-population demographic; the older people get the more health care they'll want and thus if you hold the population of physicians constant (as a % of the overall populace) the demands upon the for physicians' attention will become greater as time moves forward; you might say "so hire more nurse practitioners!" but I suspect that won't be the answer, and I think that'll be clear after the next point.
The second point is that as medical knowledge has increased over the years medicine itself has gotten much more complicated. Problems that had no answer can now be examined and more-complicated disease mechanisms and cross-interactions (etc.) can be looked at. This is particularly true in gerontological settings -- old people have lots of problems mutually-compounding each other -- but it's complicated problems aren't the unique purview of the elderly.
To practice future medicine well will require more time and attention on the physician's part; getting that time back in the face of increasing demand for physician's time probably requires more physicians, doing more-thorough work on fewer patients.
And even in the present day most major teaching hospitals only really get by by slave-driving their residents; get rid of the residents and there's not enough doctors available at prices the institutions can afford to keep the hospitals working at full capacity.
People desire more doctor-hours than exist, hence some rationing mechanism is needed. By increasing the number of doctor-hours (either increase number of doctors or doctor working hours) you can reduce the scarcity.
You can't eliminate scarcity simply by making a moral choice.
1. The high price is largely due to the need to pay off education loans. Physicians commonly finish training $200K+ in debt. Even if there were more physicians, they would have to charge almost as much just to make ends meet. To solve that you first need to find a way to cut the price of education.
2. Very few people want to be physicians, and fewer still have the intelligence and talent to do it well. Treatment by a quack is often worse than no treatment at all.
3. The only way to get a lot more physicians in to industrialized countries is through immigration from developing countries. However the political climate has turned against immigration (I think that's a bad change, but it's unlikely to reverse any time soon). And importing physicians leaves those developing countries bereft of medical care they desperately need.
4. Most physicians already work long hours. You can't squeeze much more out of them. Or if they do work longer, quality of care suffers.
There are successful models for this in use in the army (both at the level of things like ROTC and also at the level of becoming a doctor-for-the-army); if the federal government's role in healthcare expands a program like this producing physicians for "general service" is entirely reasonable.
(2) is correct in principle but without firmer #s it is hard to say if it's materially limiting.
A look at an actual chart is revealing:
http://www.aamc.org/data/facts/charts1982to2007.pdf
...page #3 (as printed on the page) has a matriculation chart:
- in the 1982-3 period 16,597 students matriculated
- in the 2006-7 period 17,759 students matriculated
...which is ~7% increase of 20 years.
The last page has a graduation chart which is similarly flat.
By comparison, the # of full-time fall enrollees at degree-granting institutions:
- in 1982: 7,220,618
- in 2007: 11,269,892
...which is a ~50% increase over 20 years ( cf http://nces.ed.gov/programs/digest/d08/tables/dt08_188.asp ). I've omitted part-timers as largely irrelevant wrt the # of future medical school students.
Now it's possible that:
- there's been a nearly-constant supply of students enrolled in college each year who are interested in and capable of becoming physicians
- ...almost the entire 50% increase in student enrollment has been in students uninterested in medicine and/or incapable of becoming competent physicians
...but that extreme of a shift seems rather unlikely.
What seems more likely is that medical schools have decided to hold class sizes mostly constant over the years, with a slight upward trend (which I'd wager is mostly accounted for by the opening of new medical schools over those decades, not by increased class size at existing institutions).
If that scenario pans out -- that the pool of qualified candidates is larger than the current matriculants -- than while your point (2) is a limit on how far the supply of physicians can be increased it wouldn't be the case that we're necessarily close to that limit..
Regarding increasing the number of doctors: plenty of people want to be physicians. In 2007, 42,315 people applied to medical school, but only 17,759 were accepted.
http://www.aamc.org/data/facts/2007/mcatgparaceeth07.htm
The people who are rejected are fairly close in scores (GPA, MCAT) to those who were accepted and there is plenty of overlap between the accepted/rejected distributions.
Let me do a little normal-distribution-fu. Assume that MCAT VR of 8.3 is the cutoff for "intelligence and talent to do it well". If we accepted every white person above that cutoff, we could train about 10,728 more white doctors per year and a few thousand more asian doctors.
(I picked 8.3 so I can call you a racist if you say you want a higher cutoff. ;) )
Regarding point 4), I agree.
In any case, while increasing the supply of physicians may not be feasible, this doesn't mean it is the case that making a moral choice can cure issues of scarcity.
I'm intimately familiar with the specifics of medical education as a family member of mine is a high-up muckety-muck at one of the world's better academic hospitals (won't be more precise than that).
There's a perception amongst outsiders that medicine is unbelievably difficult that only a handful of people qualify for medical training on their merits; a more accurate assessment is that the # of slots is fixed and the admissions are as selective as they need to be to filter down the applicant pool to the # of available slots.
It'd take time to ramp up to being able to handle that many students -- medicine is mainly taught by working under the supervision of existing experts, and there's a finite supply of expert-hours at the moment -- but the present rate of doctor-production is far from what it could be without a material drop in applicant quality.