Ironically, I haven't bought off Amazon for years, and have never left a review. I've been seeing all of these posts about gamafication of Amazon reviews and d

Ironically, I haven't bought off Amazon for years, and have never left a review. I've been seeing all of these posts about gamafication of Amazon reviews and don't understand why Amazon just don't limit the reviews on a product to people who've actually purchased it from Amazon? Ironically, I came across a small eligibility requirement, (but otherwise seems to allow reviews by anyone for anything): > To contribute to Customer features (for example, Customer Reviews, Customer Answers, Idea Lists) or to follow other contributors, you must have spent at least $50 on Amazon.com using a valid credit or debit card in the past 12 months. Promotional discounts don't qualify towards the $50 minimum. Amazon's clearly able to disallow reviews unless you've bought it from them. They're also big enough to add incentives to people who have purchases (eg. maybe 1-5% of product value that goes toward future purchases), to encourage reviews. They could even gamify the 1-5% based upon the "I've found this helpful" response, encouraging quality reviews. I just don't get it. Have I missed something?