Also, Target does have 3rd party sellers, but it sounds like they are doing it in a more constrained way. The program is called Target Plus. https://digiday.com/marketing/target-third-party-marketplace...
IMO BestBuy would have been better off extolling the virtues of having a trustworthy supply chain that doesn't circumvent regulations like Amazon does. Their retail business also means they have a better distribution system then Amazon, at least for now.
I wonder how many people buy the marketplace stuff because I know that when I go to BestBuy it's because I want something immediately or I want something where I don't trust Amazon (chargers, memory cards, etc.).
You can filter out third party sellers on Walmart's website and just buy what Walmart sells.