Evidence-based medicine, alternative medicine and weaponry change through time because of selection pressure. This means that they evolve and produce a fossil record of discontinued methods and therapies.
Any method or therapy introduced into alternative medicine will face selection pressure from two directions. If a method hurts patients to a visible extent, it will be recognised as weaponry and thrown out of altie medicine. Government regulations will forbid it and the more savvy altie practicioners will soon learn that it leads to nasty law suits.
If on the other hand a method introduced into alternative medicine turns out to be significantly beneficial to patients, it will soon be co-opted by evidence-based medicine and thus leave the altie realm.
So, there is evolutionary pressure on alternative therapies to achieve near-zero effect. This is why homeopathy is still around: its main method being the administration to patients of small amounts of clean water, it’s uniquely suited to surviving indefinitely in the alternative-therapy biotope. Homeopathic remedies can neither harm nor benefit patients.
Update 13 November: There’s a third kind of pressure on altie medicine to do nothing. Many evidence-based functional therapies incorporate drugs and procedures that can be dangerous if used in the wrong way. In order to be effective, a method must be pretty potent, and all power can be misused. Thus, an altie practitioner can never recommend a potent beneficial method due to the risk of patients ODing and dying.