I would guess that the reason that Fakespot works is that not too many people use it (relative to the total number of Amazon users) so people writing fake revie

I would guess that the reason that Fakespot works is that not too many people use it (relative to the total number of Amazon users) so people writing fake reviews don't specifically try to beat it. Anything Amazon is doing, the people writing fake reviews will specifically try to counter, so Amazon has a much harder job cut out for them.