If WoW "failed today," it would be for much more than one single reason. Even if we were in the Bizarro universe and it did fail for a single reason, I doubt that a complacent fanbase would be it. IMHO.
Nah, some people just really, really enjoy the game no matter what. People do this with music (like anything a band puts out), movies (like anything with a certain actor or actress in it, or by a certain director) and books (read anything by a certain author) so why would it be any different with a game?
It's actually not. Some people love WoW unconditionally. I am one of those people. I got bored of it which is a me issue, not a Blizzard or WoW issue. The game is amazing.
One time I played Abbey Road like forty times back-to-back and got sick of that too, and that's one of the best albums ever recorded in the history of music. Again, IMHO, and also again, a me issue, not a Beatles issue.
To assume that someone else's undying love for a subjective form of entertainment is some kind of religious cult behavior is kind of ... off-the-scale nonsense. Take the subjective thing you like most in life and realize that exact same thing makes another person retch at the thought of it. Vice-versa, while that other person is retching because of hate for a song, movie, or game, you might very well love it.
Neither of you are wrong. It's subjective entertainment we're talking about here. One should respect other's choices (when it comes to gaming, for pete's sake; we're not talking criminal activity here) and not disparage them as if they were brainwashed.