Interest in the game has declined in general and taken a downwards spiral more recently since there has been no new content for an age.
Also I think many bloggers have moved over to vlogs on youtube, becuase well thats what people want. Writen Blog or video with interesting personality, supported with game footage and guests. I can see the appeal of the writen word of course but for covering video games a video makes more sense to me.
I don't play wow anymore but still watch 'Mike preach wow' go figure =p