My doctor recommends I eat 3k-4k calories a day; back when I had trouble eating and had issues they recommended something incredibly revolutionary. Protein Shakes/Powder....
The powder I used was about 0.58 cents a calorie while Milk is about 0.175 cents a calorie. Soylent is about 0.46 cents a calorie.
150 calories for the powder
125 calories for the Milk
21 cents for the milk and 87 cents for the powder so; $1.08 for 275 calories with protein shakes and milk (0.39 cents a calorie) while Soylent would cost me a $1.26 for the same amount.
SO let's assume I'm unable to eat solid foods but can ingest liquids fairly well and I need a minimum of 3000 calories a day; that's 1125000 calories in a year or 21000 calories a week.
I'm spending about $4387 dollars a year to drink protein powder mixed with milk to maintain my diet and if I used Soylent I'd be paying $5175 dollars a year.
For a family of four to eat Soylent? 20.7k a year.
For a family of four to live off protein powder and milk? 17.5k a year.
For a family of four to live off the most liberal natural diet the USDA has? 14.9k a year.
For a family of four to live off the average / moderate level diet the USDA has? 12.3k a year.
I wouldn't even bother with it except as super expensive astronaut food.