"convenience of getting a well balanced diet served in one small dose"

Drinking a whole 2 liter pitcher of soylent is not easy. Really, go read the day by day reviews from Ars.

http://arstechnica.com/gadgets/2013/08/ars-does-soylent-day-...

I'm not sure I'd use the word convenient either. Your protypical cheap bachelor microwave meal of pizza, burritos or pot pies beats soylent on both prep and cleanup. It also tastes better and is cheaper. A bowl of cereal or oatmeal ties on cleanup and price but wins on prep and taste. Energy bars for a lunch snack win on all counts.