If nothing else, someone almost without fail will leave a one-star review that has nothing to do with the item itself. "Package was damaged, one star." "UPS left it in the rain..." If Jesus asked for reviews at Mount Olive (the loaves and fishes thing), there'd be a one-star review somewhere, "fish was a little dry, and I don't like sourdough bread. Better miracles at Joe's House of Wonder, one star." (Though I guess even in reality he got one star from the Pharisees: "shouldn't be doing miracles on Sabbath; one star.") Nothing and nobody, even Jesus, gets nothing but five star reviews.
IOW, your suggestion would be as good as anything Amazon has right now.
At least ~30%+ of Amazon's products are cheap Chinese garbage resold from Albiaba under 10+ different "brands." (private label) There's are also tons of very obvious fake and counterfeit products that could be spotted with a simple human review of new listings.