This is an oversimplification. Amazon also profits from fake reviews because they encourage consumer confidence, and most of the solutions that "random internet individuals" propose would result in some lost revenue for Amazon. The tricky part is Amazon's counter-aligned business incentive.

I put it in the same bucket as fake accounts on Twitter. My guess is that Twitter can correlate many accounts that do nothing but troll and shill for particular factions, and probably has a registry of these accounts, but they also lose MAUs when they nuke accounts. They have an incentive to wait until user growth comes in stronger than expected before they ban lots of active users.

For me personally, the biggest weakness of Amazon is commingling of inventory. I never buy things like lubricants and bearings from Amazon, even if the seller is an authorized distributor, because there's no guarantee I will avoid knockoffs from a different seller. I'd rather buy from Walmart or pay more for a specialty retailer to ship me the product, because Amazon inventory is often mixed with cheap knockoff garbage.

FakeSpot and ReviewMeta are up on different tabs every time I buy something new on Amazon, and they do a pretty good job of alerting you to scammy reviews without any internal Amazon info. I can’t imagine it’s not something an internal team could make a serious dent in.