Isn't that just rationing in a different form? If someone has $X to spend on treatment, and the best treatment costs 10*$X, then they will not be able to receive that treatment.
Do we expect that our medical professionals and facilities have the capability of providing the best treatment to everyone all the time? If they do not, how should we decide how to allocate the medical care?
I agree, that's exactly the question. Well, unless we get to a situation where literally every person can receive the best treatment for every ailment, at high-quality facilities with no waiting. If we're not in that situation, then some people can't receive the best treatment for their condition, and the question is who and when.