It's like the questions "Who is the smartest person in the world?" and "What is the tallest tree in the world?" Intelligence has been defined in so many ways that you cannot compare Leonardo Da Vinci to Chris Langan. Leonardo Da Vinci was a fantastic artist, musician, inventor, philosopher, mathematician, etc... and is estimated to have had an IQ of 230. Chris Langan, on the other hand, is considered practically the best problem solver and abstract thinker on Earth today. So who is smarter? We cannot know for sure. But I'll bet if you ask the general public who the smartest man Earth has ever produced is, they will say Albert Einstein or maybe Stephen Hawking. In reality, the smartest man on Earth is probably living (or lived) in a random country, probably not with the best of opportunities so they will never be recognized as an incredibly smart person.
Going back to the question of "What is the tallest tree in the world?", This question is probably a little easier to solve. If you google it, you will see this. But that was only discovered seven years ago. More than likely, the tallest tree ever to exist has not been found or is already dead.
In other words, we do not know who the best PvPer is, but they probably didn't play a whole lot and they probably don't play anymore.