[mathw]

Are any of these nutritionally equivalent to cow's milk?

Or human milk?

Or some kind of adult-biased version of human milk?

Oh wait, yeah. Soylent, Huel, Mana, 100%Food etc. etc. etc. are effectively "artificial milk for adult humans", at least in their liquid forms rather than the ones who sell packaged meal bars as well.

[NikolaeVarius]

Why does it matter? Milk nutritionally is simple to replace. It's sugar water with fat and some assorted vitamins. It doesn't have anything that isn't easily replaceable.