It's supposedly due to this golden standard of MMO that is widely known as World of Warcraft. That's all good and fine in the world of Blizzard and that game. In the world of Final Fantasy and SE, its fans want to play a FF title, and as far as MMO's go, a title whose standard was set by FFXI. Typically the slogan for a successor is "If you liked FFXI, you're gonna LOVE FFXIV!" Except you can't say that when comparing XI of 2005 and XIV of 2012; They are two entirely different games save Chocobos and Mithras.