This is a good point but also an unfair comparison. Walmart consumers do not have the option of walking to the factory instead of walmart. Doordash consumers can walk to the restaurant instead of ordering from doordash.
I think the analogy holds in this respect: in both cases, you can get it from the supplier, it's just less convenient, either because of having to go there, or needing to be shipped a longer distance, or needing to buy a bulk.
(Per sibling, a more relevant difference would be Walmart's having permission, but I'm not sure that's relevant to the consumer expectation; "telling you how cheap this stuff is from the source" is the kind of "facilitating you getting it cheaper" that we don't expect retailers to do.)
(Per sibling, a more relevant difference would be Walmart's having permission, but I'm not sure that's relevant to the consumer expectation; "telling you how cheap this stuff is from the source" is the kind of "facilitating you getting it cheaper" that we don't expect retailers to do.)