I suppose one could argue whether Walmart's primary value-add is sales or whether it's logistics, but certainly either of those is a higher priority than making things for consumers to sell. House brand items are still produced and packaged by some other company.

The "logistics" of Spotify's business are mostly commoditized (storage, computer, app development), but certainly they have label relationships that would be hard for a new competitor to replicate. But the key part is that for whatever reason 226 million people have given Spotify their credit card number (or local analog) which makes them pretty important to record labels.

That's pretty new in the grand scheme of things? They started making things under their brand once they became established.

I could see Spotify doing the same thing. Particularly around live ticketing, merch, etc.