You seem to be missing the point.
Genetics are a factor on other sports, not in bodybuilding. I could never beat Lebron James in basketball, play offensive tackle for the Patriots, or outrun Usain bolt on the track, but that's because they're genetic freaks. This isn't the case in bodybuilding.
I have the point exactly right. You are saying that in bodybuilding genetics arn't a factor. So why can't anyone just inject enough drugs and train for long enough and look like Ronnie.
Bolt is exactly like Ronnie. Great genetics for his sport, but without drugs, he's not running under 10 seconds, maybe not even 10.2. Ronnie would still be a big guy without drugs, but with them, he's the greatest freak ever. The problem is we all know bodybuilders use drugs, people still believe they arn't as prevalent in other sports as they are.
You can get a lot bigger with the juice. Just like if you trained for running and were running 11 seconds then trained your ass off and juiced you could probably get that down to 10.4 or something. But Bolt is starting at 10.2 without juice and 9.58 with it. Same with building muscle, Ronnie, Heath, Cutler, are ahead of the rest of us before we even start, it's maybe not as obvious early on but it's there.