I wrote yesterday about exploring not really being much of an option in many MMORPGs any more. Many games now show the way to your destination somewhere in your UI. And games like Guild Wars 2 (and if I hear correctly Wildstar as well) replaced the “find a destination” aspect of exploration by a jumping puzzle.
Killers have been out of luck for years: Free-for-all player killing has nearly completely disappeared, even the majority of EVE players are rather safe from being killed most of the time. And it is arguable whether a carefully balanced battleground provides the same motivation for a player killer.
Socializing has taken big hits too: You don’t need a group to play through most of the content. Gone as well are the times of “we need to wait 20 minutes for the boat, might as well chat with that stranger”. Even the most socially advanced activity of a MMORPG: Planning a raid now can be done without people exchanging any words.
What remains is games that seem to be pretty much exclusively tailored for achievers. Which, judging by the comments I get, suits some people just fine. But even there developers realized that it was impossible for average players to have a constant stream of real achievements, so they designed “achievement systems” which basically handed out rewards and medals for just showing up and playing the game. A few real achiever types started making an achievement out of NOT receiving certain achievements in the game, because it turns out that not getting them is a lot harder than getting them. If in a typical MMORPG which is all about kill ten rats quests you get achievements for doing quests and killing monsters, it is harder to try to level up without getting those achievements.
But ultimately the idea of Dr. Bartle was that people play MUDs (and by extension MMORPGs) out of different motivations. And the Bartle Test suggested that most people have a mix of motivations, and aren’t purely 100% motivated by just one thing. Thus for example the concept of somebody having grown bored of the game, but continuing to subscribe because his friends are still playing. By turning MMORPGs into games which are nearly exclusively about achievements, and don’t give much room for exploration, killing, and socializing, you end up with people being less motivated to play. Which could explain why people leave new games after such a short time these days.