Thanks for posting on this, Chemeng. I heard the teaser for it on NPR while driving to get my son from school, but didn't actually get to hear the full piece. I've been bothered by the overuse of "legend" for some time, particularly because, to me, the word does mean something unreal or mythical. Among a number of other definitions, AHD gives:

1a. An unverified story handed down from earlier times, especially one popularly believed to be historical.

So when I hear someone described as a sports legend, I get the sense that perhaps that person might not have really existed, that he was the Paul Bunyan of relief pitchers or something.

Another AHD sense captures the Ted Williamses of the world: 2. One that inspires legends or achieves legendary fame. But there seems to me such a difference between being a major modern celebrity and being the Loch Ness Monster, or Tarzan, or even Johnny Appleseed, who we know existed historically but who has achieved such legendary status that most people think he's just a story.