The reason why Starcraft has been successful as a spectator sport is because it's more than just the game. I've been watching Brood War for ages, and I haven't touched the game in years. I have watched the rise of Boxer, and the phenomenal players after him that would come to dominate and redefine the game. I was there when iloveoov ended the era of micro and brought the new age of macro. I was there when Savior made people wonder if it was possible for anybody to win in this game.
Maybe it was dumb luck, or maybe Starcraft was just that expressive of a game, but the pro scene that developed had a real storyline. You weren't there just to watch great games. You were there to watch heroes and villains, and the player's personalities shone through the games. I don't care how good the games are, if it were computers playing each other, there would be absolutely no appeal for me. I figure the appeal is a lot like the reason people watch pro wrestling.
I would say the main reason why western games haven't reached brood war like popularity is because the players themselves are just stupid to watch. There is no organized effort put into making such an image, so we just get to see them in their natural state, a bunch of assholes trying to brag about how good they are at the game and win money off of each other. Kespa, the regulatory agency for brood war, has done a lot to cultivate the images of the players as something presentable. Again, unless you can make the event more than just about the game, if you can't create a storyline about the players that people actually want to watch, you're not going to have fans sticking around.
It's pretty bullshit to say that games haven't got spectator status because they're not accessible. None of the Korean fan girls that watch starcraft know a thing about the game beyond having enemies in your base is bad. They're not there to watch good games of starcraft. They're there to watch Bisu or Jangbi, or whoever their favorite player or team is overcome their challenges.