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.)