Sure, but at the same time one could sell their product in different stores, or even D2C online.

The store analogy also has very limited switching costs, for example if Walmart stops selling brand X of potato chips, it's inconvenient but not impractical to go out of one's way to buy them at Target. It would be different if buying potato chips at Target would involve throwing out everything one has bought at Walmart and buying the same Target-equivalent merchandise (ie. switching from iPhone to Android, one would need to buy equivalent apps).