> This perspective is very frustrating to me. Why in the world would a sane person take a drug with unproven efficacy when others with proven efficacy are available?

Because they don't want the side effects of proven treatments, and they hope that snake oil will help them.

If people were rational about their health, homeopathic supplements, and other similar bullshit wouldn't be a billion dollar industry.

If you can't prove that your treatment works, you shouldn't be advertising it as a medical treatment. Advertise it as a non-medical non-treatment.