To list your product on Amazon as a seller, you pay $500 per year as a "review incentivization fee." The algorithm randomly selects buyers and emails them 1 month after their purchase. They are offered $10 to write a review. The chance of being randomly selected as a reviewer auto-adjusts to target a goal of 50 reviews per year, and no one except those people is allowed to post reviews. Also, reviewers can update their reviews later if their impression of the product changes.
If a seller wanted to keep farming reviews, they would now have to buy up the vast majority of their own inventory in the hopes of being selected. Also, my system prevents people who are experiencing one-in-a-million problems (or who are just habitually disgruntled) from dominating the conversation.