Regardless of the eye test (which visibly shows he didn't have that range), again, he could not shoot a free throw, and he shot them MANY different ways (which was allowed back then). If he couldn't pop wide-open 15-foot jumpers at better than 51% over the course of his career, how is he able to pop 16-20 foot jumpers, defended, shooting them any way he wants as well?
It didn't happen. Wilt was a dominant force down low that had decent range for a big man. He did not have Hakeem range, or Dirk range, though, and that should be an undisputed statement.
Yao Ming stood 16-17 feet from the rim and dropped 10-15 straight shots. THAT is range for a big man. He did it on camera. There's proof of it. He did it during games.
For some reason, you want people to believe otherwise. I don't have any reason to prove that Kobe, Jordan, Wilt OR Kareem are the greatest scorers of all time, because I can argue for all four.
However, Wilt was not all over the court. Outside of the paint? Of course, but not 16-20 feet outside of it. Did he make shots from out there? I'm sure he made a few, like Rajon Rondo has a few threes (75 in his career, around 10 a year), but not as often as you're trying to point out.