Most people do not have all the facts or have not been educated about the needs of the Human Body. It is that simple.
They are possibly afraid of making a commitment, or adhering to new disciplines, or heard too many stories about the failure of diets, and/or do not understand the really simple needs and requirements of their bodies.
It is seldom heard, if ever, that anyone who provides their body with its needs is suffering hardships or pine for bad habits.
Their lives are generally more fulfilling, energetic, disease free and being enjoyed to the utmost.