Yes, it is unfortunate that such a lack of savior faire is characteristic of those at the apex of gaming. Maybe it's akin to the lack of mental faculties most sports heroes exhibit in post-game interviews. Perhaps that is why Wiebe is portrayed as the hero in King of Kong, to give us a friendlier, more modest face. I guess we should be happy that we aren't associated with rapes or biting ears off, etc.
And I don't know about you, but I think it's more Donkey Kong, not Pac-Man, that invokes Mitchell's image for me. And even having said that, I still don't really associate those games that I spent hours playing in my youth with the top scorers I've only heard of and seen briefly. These small nuggets of fame that pro gamers receive are probably due to the fact that games are more interactive than sports. Gaming still isn't widely considered a spectator sport; it's much easier and rewarding to play them at home or even watch someone play them at your house. Even in a "home spectator" setting, people don't watch the player unless they wield the controller wildly. In much of videogame culture, the player is not the focus; the game is. So I don't think gaming needs Mitchell, Ashman, or any of them. They don't serve a purpose; they simply exist.