I believe: The majority of the players in World of Warcraft are first-time MMO players. We all know how hard it is to leave that first MMO, and the popularity of WoW makes it even harder because it’s not about the game as much as it is about the people you have met.
I believe: The majority of those first-time WoW players will eventually realize how much time they have “lost” playing WoW and will not move on to another MMO when they do finally decide to quit WoW.
I believe: New MMOs will not have a lot of success targeting the first-time WoW players and will have to rely mostly on people new to the MMO genre as well as the old-school MMO players that try them all hoping to find “The One”.
I believe: The first-time MMO players that do leave WoW for another MMO will have a very hard time finding another MMO to equal their first and will not give new MMOs much of a chance unless they dramatically improve on the WoW gameplay experience.