I'm convinced that the Alzheimer's field is one of the areas of research that will be looked back upon with disillusionment.
Tau tangles and beta plaques have been fiercely and dogmatically pursued as causes and therapeutic targets of Alzheimer's disease. However, it is becoming increasingly clear that these aggregations are likely a consequence of the disease that does not necessarily present an avenue for therapy. I.e. the harmful part of the disease probably acts upstream of or in parallel to the accumulation of the tau and beta aggregations