Any person can become "big" but that does not mean they understand how the body works. People have to understand that everyones body is different, and just because your workout works, it may not work for others.
My brother is 6'2 and 185, but can put up 285 and has never taken a SINGLE supplement. Does that mean he knows more about working out than anyone else? No. But he has taken the time to take anatomy, biology, and chemistry courses to learn more about metabolism, enzymes, etc. It doesnt hurt that he can lift that much, but it helps that he takes courses that teach him about the human body.