In the lucrative world of massive multiplayer online role-playing games, or MMORPGs, Activision Blizzard's World of Warcraft reigns supreme. Or, at least it used to. The eight-year old phenomenon — which lets dedicated gamers assume the identity of carefully curated avatars such as warriors, mages, and priests — seems to be losing its shine (though recent studies have suggested it can help give seniors a brain boost). At the height of its popularity two years ago, the title, known as WoW, boasted 12 million global subscribers willing to shell out $15 a month. That fell to 10.2 million in the fiscal quarter ending March 30, and, as of the end of the second quarter (ending in June), the game's player base plummeted to 9.1 million — its steepest drop-off yet. Now Activision Blizzard's investors are sweating, and the company's stock fell steadily following the announcement. Why are WoW players, oft considered the most rabid out there, finally abandoning their accounts? Four theories: 

1. Gamers jumped to Diablo 3
While the extent of the loss is a "surprise," the fact that WoW is losing subscribers isn't, says Pete Haas at CinemaBlend. Blizzard launched its long-awaited hack-and-slash title Diablo 3 in May, "so many usual WoW players have let their subscriptions lapse so they can play that." There are only so many hours to go around. 

2. There are too many free alternatives
Competition is getting stiff, especially as rival game-makers such as Electronic Arts make their MMORPGs available to players for free. Titles like Star Wars: The Old Republic are waving subscription fees, instead charging players money for virtual items and access to extra in-game content. "The availability of free multiplayer online games is definitely cannibalizing subscription games," Michael Pachter, an analyst with Wedbush securities, tells the Los Angeles Times. "It's just not a growth industry." 

3. Activision Blizzard is turning off hardcore gamers by appealing to the masses
This fall, the company will roll out its newest WoW update, "Mists of Pandaria," says Paul Tassi at Forbes, which lets gamers select a radically different kind of avatar: Giant kung-fu-fighting pandas. Such a silly, Disney-esque addition is hardly the kind of savior that would "persuade the hardcore MMO crowd that the game isn't catering too much to casuals." 

4. It's been out for a long time
The simple fact is "WoW is just getting old," says Tassi. Released in 2004, it's showing its age, despite a fair number of expansions. "Historically, the game has seen a usage decline toward the end of an expansion cycle," says Stefanie Fogel at VentureBeat, and WoW is reaching the tail-end of its most recent update. But usage rates are cyclical, Activision Blizzard chief executive Bobby Kotick tells the Los Angeles Times, who expects the game to pick up subscribers when "Mists of Pandaria" is released in a few weeks. "The numbers that shift up and down in terms of subscribers are not reflective of the franchise. The franchise is enduring."