Last time I checked, Soylent comes in packages, and requires water to eat.
So sure, you can combine your nutrient goo powder into a single sack, and thereby save a tiny fraction of the weight of the food (and water) itself. But you're splitting hairs.
I picked a mountain house pouch-based product at random on amazon, and the packaging weight was .06oz on a gross of 5oz, or 1.2%. Which is, of course, nothing. I have heard exactly zero people, ever, complain about the weight of their dried food packaging. I've heard lots of people complain about camping food being boring and flavorless.
If you like Soylent, fine, but the claim that this stuff is the obvious best product for campers is silly.