It did benefit from the stars aligning properly at just the right time. I'd day luck does play the biggest factor in its subscriber numbers.

I can't stand WoW now but I'll not take anything away from the game because of that. They would've never sustained such numbers if they didn't put out an awesome game. It's deserving of the top spot.

It does, however, taint everyone's perceptions of every other MMO. Everything else is judged by how WoWish it is. I think that's the only downside. People get comfortable with a certain style and system and they're unwilling to leave their comfort zone and give something else a fair shake.