Do you ever ponder the scope of human suffering before widely available modern medicine came into play. I think the history fantasists forget or remain ignorant of the fearful suffering before the 20th century. And, I should add the obvious, for many people that fear and suffering is still the status quo.
To imagine any number of historically inspiring times as healthy is largely ignorant. Much of humanity in the now-developed world until the modern era was suffering greatly.
I can't believe the lack of knowledge some have, to an ancient person a herb that helps stop itchy skin would be a god send or witch craft. It is a cliche that middle-ages witches were likely herbalists or those who got on the wrong side of a witchfinder general. But, it isn't unreasonable in some cases.
Imagine a healer of this kind in any region of the world a thousand more years ago, he or she might be called a magician, a prophet or the son of God. To uninformed people and slightly informed quacks a few herbal treatments might seem to be as magical are curing leprosy. And, as our history is warped by story tellers, one who is said to cure a horrid disease simply helped ease their suffering.
Maybe then, as is common, superstition filled the gaps for the people. To be told an old potion will cure an ill might be understood as a miracle, and refined medicines that are hard to replicateseem to be even more remarkable