I am partially disagree with you,
if you want to say that having a body like rusty jone is impossible,

firstly, gene is affecting the time of process which is needed to achieve the goal,
whoever with mesomorph and muscular gene, indeed will achieve this kind of goal in a short time.

5 years diet is not a fix time, may be varies for one to another.

I believe and very sure if everybody can shape their own self like whatever they want,
as long they know "how" and and really dedicated to put the effort in their regular life style

cheers!