No specific reason was given for the move, but a farewell letter posted on the site attempts to soften the blow: "This is not an easy decision, but there comes a time when it's best for our developers to move on to the next adventure, and that day has come." In the closure FAQ, SOE also promises a celebration at the end of the game's run.
To appease its remaining EQOA customers, SOE is offering three months of gold membership in both EverQuest and EverQuest II for current subscribers. This consolation prize will become effective on March 16th. SOE will also not be charging current players during March.
EQOA has always been the smallest member of the EverQuest franchise since its release in 2003 on the PlayStation 2. We covered it in our Game Archaeologist column late last year and were impressed by the passion and memories that the game's fans shared.
[Thanks to Omali for the tip!]