[maxander]

That the FDA does not regulate the practice of medicine is technically true- doctors can and do use (approved) medicines for non-approved uses. But as you also mention, this informal, "non-evidence based" approach has downsides such as the risk of malpractice suits. If a doctor tries treating a sepsis patient with corticosteroids and vitamin D, instead of with the current "evidence based" standard of care (massive doses of antibiotics,) and then the patient dies, the patient's next of kin can sue for massive damages, potentially ending the physician's career- despite it being the medically more effective thing to do. As far as the courts would be concerned, this could be equivalent to the doctor opting for homeopathic medicine in place of antibiotics; one treatment not supported by the evidential standards of medical care is about as good as another, to a lawyer. Since doctors can't risk their medical licenses on a daily basis and stay doctors, they treat patients with suboptimal methods, and people die because of it.

So to say that the issue is funding for FDA approval is probably an oversimplification- equally powerful studies without FDA involvement may or may not suffice, that's a question having to do with law and other non-science factors. But the FDA has established what is the broadly recognized "gold standard" of establishing the medical effectiveness of an intervention.