A lot of medical discoveries are hardly "new", many revealed long ago and forgotten or simply ignored. The medical profession is rather hidebound and doesn't take well to change or to admit it is wrong. The dietary fat canard(ooh that evil fat, let's replace it with sugar and carbs...) pushed by the food industry and sanctioned by the medical industry, is an egregious example that that has ruined many lives and helped create an epidemic of obesity. 

https://tonic.vice.com/en_us/article/3bkaan/were-all-guinea-pigs-in-a-failed-decades-long-diet-experiment


Atul Gawande nails it on the epidemic of unnecessary medical care:
http://www.newyorker.com/magazine/2015/05/11/overkill-atul-gawande


I put the words "never happen" in the same generally useless category that holds such bromides as "it's different this time", nobody knows the future. Many of us have causes we believe in, you put your energies where you like, and I'll do the same, thank you.