The limiting factor, as I understand it, is residency slots. Residency slots are, for some reason, principally funded by Medicare, so they are funded by Congress, which has for the past several decades not increased that allocation. Apparently that's starting to change?

In my opinion though, I can't see why the number of doctors should be something that is principally controlled by congress at all, and ideally some other method should come about.

Until that happens though, it's up to Congress to fix this.

I've read about it and came upon the same answer as you just gave, but I'm not satisfied with it.

Looking around the world, it seems to me that most developed countries (if not all) suffer from the same problem of lack of doctors. Some mask it by pulling doctors from poorer countries (including poorer developed countries), but it seems like there's a lack of doctors everywhere. If that's the case then Congress can't really be the only limiting factor.

Why are there no developed countries that have far too many doctors? The only countries that I can think of that export doctors are Cuba and third world countries.

You need to be smart, hard working, dedicated, and interested in medicine. That’s going to be a limiting factor. Add in high tuition and a public that hates you, and it’s hard to motivate.