Its fairly disingenuous to call $4/meal expensive and then spend time cooking - especially after you talk about the importance of not wasting time. You go from valuing your time above all else to claiming that its worth almost nothing.
I agree with you. Hence, the reason that I completely support the idea that someone else may face a situation in which Soylent becomes the most valuable option. Without a doubt, I think it is better to eat a healthy Soylent meal than cheap fast food. While I do think that $4/meal is incredibly cheap for the cities in which I live, Paris and London, we still are able to eat on less than that amount per meal by shopping uniquely in the produce section of the market.
My logical jumping-off point is that healthy eating habits are the most important factor in long-term health, which leads to more time to devote to meaningful activities because of increased life span and a decrease of down-time due to sickness. In addition to the value derived from long-term health, I think there is also a value to be derived from the enjoyment of food and the exposure to a wide variety of culinary-styles. However, that is a valuation that other may not share.