The Medical Guild didn't have much to offer in the early part of the 20th century. The Osteopaths [possibly] had much better results at their hospitals during the Great Flu of 1918, for example.
Science started to make some progress figuring things out, but then the snake oil salesmen regrouped and used the cloak of 'science' to sell their 'prescriptions'. For example, Statin drugs might prevent a few heart attacks, but just cause side effects for 90+% of the patients who take them.
Pfizer, et al, are trying to restore estrogen/Premarin (a prescription derived from PREgnant MARes' urIN [1]) to its former glory, even though estrogen treatment was always known by actual scientists to be harmful [2].
Robert Whitaker has provided an indictment of conventional psychiatry's use of 'snake oil' [3], and a science writer recently voted to indict [4].