It's more like a meal replacement shake than dog food. It's very much like Ensure or Jevity or whatever. All of those do the same basic thing of trying to cover basic nutritional requirements.
The big difference is the marketing. Most of those products assumed you were either unable to eat or trying to lose weight. Soylent is roughly the same product but marketed to people who aren't interested in eating.
I think there's a significant difference in that Ensure and Jevity aren't meant to be sustainable as a long term food source, and don't optimize for cost per meal.
There are very many products that are complete nutrition sources.
The fact that the manufacturers fear the regulators enough to slap disclaimers on the products and to carefully differentiate between over the counter product and specialist medical product should give Soylent users paise for thought.
Those companies, with dietitians and registered nutritionists and years of data from patients know that patients need careful monitoring.
people like that are often times under medical care, and have very little physical activity. Nutrition is an easier thing to balance with the aid of daily blood testing and a low caloric requirement.
As someone who experienced the reality of tube feeding, it's not so easy as a single product. I was given supplemental amino acids, fish oils and vitamin boosters which were powdered and mixed with sterile water before use, alongside whatever the meal supplementation was during that day (things similar to ensure)
The big difference is the marketing. Most of those products assumed you were either unable to eat or trying to lose weight. Soylent is roughly the same product but marketed to people who aren't interested in eating.