Whilst the idea of Soylent make sense, one cannot ignore the simple fact that every one of us is biochemically unique and thus we have different nutrition needs. There are averages on which Soylent can be based, but there are cases where averages are far from enough. Let’s take the case of people with the Pyroluria condition, who have signficant higher needs for zinc and b6.
For people with this condition, Soylent has to be further supplemented with additional Zinc and B6. Thus people still need to take their time and understand their nutrition needs and not just buy soylent and that’s it.