I think it goes against a lot of people's idea of efficieny. Why should each person need to research, source, and mix their own MRP if we have similar needs?
The deal is that people have to know what their body needs first and foremost. Gain? Lose? Maintain? All are different goals and methods. Solyent advertising as an off-the-shelf works-for-all-people might be fundamentally true, but I don't think it can be argued that it's the ideal for each and every person.