People need to keep in mind that MOST bber's are short 5'4, 5'6 and the tallest being around 5'10 or 5'11 in modern era. Don't see much muscle being packed on on those frames naturally.
I consider big to be around 6 feet and above. Genetics are one thing, but for most average joes with average genetics give them access to the drugs these "elite," pros are on and they can be just as impressive, maybe not win pro show, but pretty close. There are lots of guys walking around with potential to be "elite," pros, but the general public could give two shits about turning pro and impressing male audiences. That and the amount of drugs it takes. Most however, would rather try to play pro football or basketball.