My two cents
Only in bodybuilding does it seem the perception exists that anyone if they train hard enough and exhibit extreme dedication can become the best in their sport. What is needed is not merely good genetics, but great genetics. Tiger Woods is super dedicated but his golfing prowess is overwhelmingly down to the fact that he was born with a gift to master the intricate techniques of guiding a ball around a golf course. In tennis Roger Federer trains like a Titan but he has won a record 17 Grand Slam titles because fate bequeathed him the ability to attain world beating racket skills. Same with bodybuilding. To be a champion you need those great genetics. Being born with narrow clavicles, wide hips, short legs, a long trunk and short muscle insertions is not a resume destined to disrupt Phil Heath’s sleeping habits. So for starters to make it at the top level you must have a good skeletal structure.
In addition what is then needed is a superior ability to respond to progressive resistance training and accumulate muscle mass. Kerry Kayes, British Masters champion, past promoter of the English Grand Prix and contest prep advisor illustrates that latter point very well: “Imagine that a normal person is born with two bricklayers inside him which help to build muscle. And imagine that a future Mr. Olympia is born with seven bricklayers inside him. The normal person may take a load of gear and double his muscle building ability and end up with four bricklayers, which still isn’t as many as Mr. Olympia beforr he starts the gear.” Following on from that rationale it’s a personal contention that it is those less genetically gifted who take the most drugs: But that’s an argument for another time.