“Either all our ancestors up until the discovery of penicillin were a bunch of superstitious ignoramuses, or they discovered some natural remedies that were effective for many ailments.”
Probably a little of both.
A lot of drugs are, or are derived from, natural products.
In olden times, a person would work 12 hr days for a season. When they had down time they had to do something. Most took up hobbies or research to better themselves. That is how a lot of this came to be.
Nowadays, our idle folks spend their time in trivial pursuits and mindless entertainment.