EVE is nothing if not walking to the beat of it's own drum when it comes to the MMO market. In the gameplay realm this is seen in it's emergent gameplay and astounding levels of player freedom. In it's development it can be seen in how CCP is privately owned and answers to no publishers or stakeholders except the players themselves through the Council of Stellar Management. In it's business success this can definitely be seen through the game's subscription numbers.
Usual subscription numbers in an MMO tend to spike a bit after launch, rise for a while, and then sharply drop off. There are any number of ways this behavior can be explained. Maybe a lot of people bought subscriptions when the positive reviews and hype came rolling in and then decided they didn't like the game, or perhaps when players hit the endgame and have achieved everything that can be done they let their subscription lapse. EVE's subscription trend is different.
EVE Online has shown linear, positive subscription growth for over 9 straight years. Even with the huge drop in subscribers during summer of 2011, with the wildly successful 2011 winter expansion, Crucible, they managed to make it in just under the wire with a positive subscriber count at the new year.
Resizing the image to fit in this site's 620px restriction makes it hard to make out, but EVE's line is the one with bright blue circles. Nearly every game on this graph shows exponential growth at some point, before a huge drop in active players.
The life cycle of an MMO is a vicious one unless you can keep delivering content to the players, which can be difficult with how efficiently they can consume it. WoW has managed to hang on longer than most
, but you can clearly see that unless something drastic happens, WoW reached it's peak in the 2009-to-late-2010 time frame.
EVE succeeds in maintaining a solid player base with constant growth for a few simple reasons that aren't even directly related to the quality of the game, which is why it continues to thrive in spite of so many people finding it horrifically boring.
Firstly, EVE has no endgame, at least not in the traditional sense. There are no levels, so you can't 'max out', and there is no static endgame content. It's all player-driven, which means that as long as there are players, there will always
be content for anyone who wants it. All of the stories you hear about epic battles and back-stabbing subterfuge were achieved and masterminded by players.
Secondly, improving character skills in EVE takes time, not effort, and you are not restricted by anything resembling a 'class'. You can choose one of 4 races to play as, but every race can train into every other race's ships with no penalty. There are enough skills in the game that training them all would take longer than the game's servers have been open, so it is impossible to learn everything. There are learning implants to make training go faster, but it's still time-dependent. This keeps players from madly grinding up through the ranks and then quitting after acquiring every skill.
EVE may not be the most successful MMO (WoW will probably always hold that title), but it has proven through it's unique game design and 9 years and 17 free expansions of consecutive growth that it is far and away the most consistent.