It's not clear to me why Service Merchandise (and its predecessors like Best Products, Consumers Distributing, and Unity Buying Service) all failed back then.

It's not clear to me why Service Merchandise (and its predecessors like Best Products, Consumers Distributing, and Unity Buying Service) all failed back then. They certainly couldn't compete now with the economies of scale of Walmart or Amazon. It's odd that online grocery shopping is so huge now given Webvan's crash and burn in that space not all that long ago.