it makes sense that the people with the potential to be the best may not compete, there could be a guy out there playing football who has the potential to win the olympia, but it's not like he's in olympia caliber shape right now and just needs to step on stage.
same deal with the lifters. there are probably guys out there who could break records if they went to a straight lifting routine and scrapped as much running as they do, but as it stands they aren't nearly strong enough.