What you're experiencing is called dropshipping, and it's becoming popular because amateurs are seeing it as a "get rich quick scheme." There's a product called

What you're experiencing is called dropshipping, and it's becoming popular because amateurs are seeing it as a "get rich quick scheme." There's a product called Oberlo (https://www.oberlo.com/ https://www.oberlo.com/) where you can easily browse Chinese items for sale and add them to your own Shopify store. Then you can use a free plugin to integrate Shopify with Amazon. That's why you're seeing a million of the same item, because it's tons of people browsing the same products with this same setup.