A perfectly balanced meal in a glass? Of course it's popular. Most people don't come close to "balanced meal", and suffer the consequences via various illnesses. Most people have other things to do most of the time than making and eating awesome food; for a great many it's more an inconvenience of making hunger pains go away for a few hours.

Soylent's creator makes it very clear he still enjoys making and eating awesome food - he just doesn't want to deal with doing so 1,095 times every year. If anything, he appreciates good food even more.