But then they want the brand, so the seller gets to extract a premium for the brand even if you knew their COGS to the penny because it's actually worth that mu

But then they want the brand, so the seller gets to extract a premium for the brand even if you knew their COGS to the penny because it's actually worth that much in additional sales and they both know it. The thing where they make a worse version of the product isn't Walmart screwing the seller, it's the seller taking the short-term profit option by screwing the [Walmart] customer until the customer notices. And then the question is whether the customer notices whether the product is worse, or the customer notices that the product is worse from Walmart. Also, a lot of the store-specific SKUs aren't actually different whatsoever, they just put a different number on the box because it gets them out of MFN clauses with other retailers and the retailer likes it too because it gets them out of price match guarantees since nobody else has that SKU to match against.