ever since the discovery of amyloid plaques, it's been an open question. Are they causative or a symptom? Would reducing or eliminating them help treat the disease? There is lots of data that supports amyloid as a disease treatment target, particularly in animal models. Of course the abject failure to actually develop a good anti-amyloid treatment that actually provable and significantly mitigates the disease weighs against the idea that amyloid is a good target. And the high profile frauds that have been discovered haven't helped. But, the biomedical community are not a bunch of morons. All these drug companies wouldn't have spent these billions of dollars on anti-amyloid and anti-tau if they were such obviously terrible ideas.