Lots of comments here of the format "every store does this."
No, no other store operates this way. Walmart and Costco do not have a little flea market of third party sellers inside their stores who run their own logistics. This would be more like Amazon being both an anchor tenant and owner of a mall, and requiring that every other store within the mall provide all their sales information, then rapidly evicting all the successful stores and replacing them with knock off stores that they also own.
That is true, I picked a bad example, although Walmart Marketplace is a very high touch service which is expressly targeting sellers that they don't want to cover themselves.
isn't this effectively how home depot and lowes are run? basically everything is on consignment, and they occasionally spin up private-label versions of tools to sell?
Not the same thing. Check out other relevant responses here, too. In short, Home Depot or Lowe's are buying products to resell. They are the seller themselves. OP's argument is that Amazon is the platform facilitating the sale -- hence the mall owner.
No, no other store operates this way. Walmart and Costco do not have a little flea market of third party sellers inside their stores who run their own logistics. This would be more like Amazon being both an anchor tenant and owner of a mall, and requiring that every other store within the mall provide all their sales information, then rapidly evicting all the successful stores and replacing them with knock off stores that they also own.