Quoted By:
Ultimately there's only two ways a market leader can be dethroned, either they fuck up and drive a large portion of their fanbase to their competition, ala what happened to wow, or they get upstaged by another product that appeals more powerfully to their core market, like what Dota and mobas did to RTSes back in the early 2000s.
It's interesting to note however that cover has gone through three incidents that should've caused their audience to desert them en masse like wow, the chinkout, Rushia's firing, and tempus 2, but somehow they are still going as strong as ever.