Polymath writes: "The first reason is really quite simple. The chances are that anybody playing WoW has already invested a great deal of time and money into the game. Walking away from all that effort to start a new, similar experience just doesn't seem like a smart move. In short, too many MMORPGs try to replicate WoW with a new license, rather than try something new.
Star Wars Galaxies, now generally regarded with distain, was once held as something to behold because of its complex gameplay. However, in the wake of WoW the game was drastically altered in order to try and capture players away and, ultimately, became something that people didn't want to play. A similar fate could befall the upcoming Star Wars: The Old Republic if Bioware is not careful. Even as a huge Star Wars fan, I'm not going to leave behind all my work in WoW for a similar experience, even if it does have a license I find more appealing."