In the chemistry sense, but not in the ingredient sense. If I press an orange into a glass I've added 100% orange juice. Notice that I never explicitly added any water to the glass. Whereas if I make it from concentrate I'm adding tap water as an input.
What's the difference of the resulting mixture, chemically?
I clearly stated that there isn't one ... ? It's a matter of if you care about process (ie inputs) versus end result. Generally labels are already much closer to the former than the latter given that they typically list multiple natural products.
Yeah, a small container of powdered fruit to drink wouldn't have the same benefits.