OP is saying that Amazon has exactly zero reasons to change its ways if it makes zero difference to their income. They deleted the reviews of a reputable customer. Will he keep on buying from Amazon like he did before? Yes. So will there be any downsides for Amazon for deleting reputable customers' reviews? No. Money will keep flowing, resentment is irrelevant. So, they will keep deleting reputable customers' reviews, because changing that takes effort, and effort costs, and cost have to lead to more profits to be justified.