The solution starts with manually verifying products. I'm not convinced that it's impossible for Amazon or other stores to have a quality verification system where they have people hired specifically for this purpose. Maybe even a third party could specifically do this. You don't have to do it for every single item, just do it once whenever someone wants to list a product on the platform. Whenever reviews start complain about bogus products, investigate, and if they changed the product from the last time you verified it, remove them from the platform for a period of time.