Do Facts Ruin Legends?

"The truth greater than the facts is that Arthur was considered to be a king by most medieval monarchs, who sought to imitate him and even to bring him into their genealogies." (Snyder 8)

Thinking about the line between reality and myth, I started to wonder if the actual existence of Arthur really mattered. Sure, it would be great to know that this legendary hero was a real person for history's sake, but I think the facts of life would only take away from his legacy. When a larger-than-life figure loses his mystique, he becomes human like the rest of us. Would tales of Paul Bunyan be better if he was just a normal lumberjack? Would Theseus be iconic if he didn't slay the Minotaur?

The story of King Arthur is the established truth of history and legend. Does it really need to be ruined by fact? Does the world really need more humans?