There are so many variables to consider other than simply stating that drugs are 100% responsible for creating a good bodybuilder. Some previous posts touched on androgen response (which is why guy "X" will put on 20lbs of quality size and guy "Y" will put on half that, even if they take the exact same cycle). Another important genetic-related quality is muscle recovery. Again, X and Y could do the same workout with the same weights, but X stays sore for only 2 days while Y stays sore for 4 days. A final genetic consideration is the individual's tolerance for gear. Just like some people can smoke or drink for 50yrs and live to 90, some guys can handle heavy drug use, others cannot.
Another issue which I am sure GH15 can confirm is that probably 95% of competitive BB'ers don't even lift weights while they're "off." It doesn't start out this way, but once you see that there really are no gains to be made, the motivation to hit the weights just isn't there. Personally, I don't agree with this philosophy, but I do understand it. I always thought that is was best to hold on to as much size offseason, keep the range of motion intact, and it really is a part of my routine, so to abandon lifting even temporarily was never a consideration.
Finally, too many guys jump into gear way to soon, failing to establish any real kind of "base" muscle. For them, they are indeed "ALL DRUGS" and once you pull the needle, they deflate like a balloon. I know the haters don't want to believe it, but there are guys who lifted for a long time (5-10+ years), who actually KNEW what they were doing while in the gym (an issue for another thread...), ate enough, lifted heavy, and then juiced, and as long as they keep lifting, will never lose the base they built. It's not that hard to walk around at 6', 240-250lbs with decent size and b/f ratio if you did all this for 20+ years, but how many do? Hell, some of you aren't even that old!
Every single person who ever posted on this forum could take whatever Barry Bonds or Clemons took and would never be able to do the things that they have on the field. In the same vein, taking the same exact cycle as Coleman won't allow you to win a single Olympia title, let alone turn pro. Besides the fact that you'd be pissing blood after 3 months of what he's on, you'd still have to have the time, dedication, discipline, and most importantly, the diet. Not just knowledge of the diet, but the will to stick with it.