It's a little bit different because Amazon claims to be a marketplace at the same time as curating its own specific product offering. It would be kind of like if a mall required all transactions from independent stores in the mall to go thru the malls servers and then the mall started its own product lines to sell based on that data.
That amazon does has been common knowledge since Amazon Basics first appeared. Obviously, Amazon is enjoying the enviable position enjoying being the mall, the payment processor, and everything else.
