The doctors prescribing the drugs don't know they don't do what they're meant to. Nor do their patients. The manufacturers know full well, but they're not telling.
Missing data poisons the well for everybody. If proper trials are never done, if trials with negative results are withheld, then we simply cannot know the true effects of the treatments we use. Evidence in medicine is not an abstract academic preoccupation. When we are fed bad data, we make the wrong decisions, inflicting unnecessary pain and suffering, and death, on people just like us.
Jupiter retrograde in the Crab - Release From Pretending