Amazon has been full of garbage since they started going 3rd party shipping. In their very early days vendors shipped everything to Amazon in Seattle and it was inspected before being sent on to a buyer.
Not true. I've been selling new and used books, cds, dvds, vhs on amazon for close to 20 years. In the beginning, all third-party sellers shipped items directly to buyers (know as fulfillment by me - FBM). About 12-15 years ago, amazon started offering third-party sellers fulfillment by amazon - FBA.
Amazon has never inspected items for quality/genuineness. They only respond to complaints. Savvy third-party sellers who use Amazon to fulfill orders request that returns be sent back to the seller and not put back into inventory. This is because customers sometimes return damaged merchandise or different merchandise and since amazon doesn't inspect returns, the damaged products end up getting sent back out (I've been on the receiving end of a couple of those). If amazon inspected products, they recently wouldn't have received $300,000 of returns from one buyer who had filled the packages with dirt.
US sellers have been complaining about Chinese products and practices to Amazon for years, but amazon makes a lot of money off of China. US sellers complain to amazon about Chinese companies selling counterfeits of their products. If the seller can get amazon to take the counterfeit down (by making a test buy and going through a process with amazon foreign CSRs who rarely understand what's going on), within days another Chinese seller will be selling the counterfeit product. It's a never-ending whack-a-mole game.