PC Gamer just recently posted an article on Take-Two Interactive CEO Strauss Zelnick and his statement pertaining to the success of MMOs and whether or not they would succeed because of being published in the United States, or internationally published.
You can read the article here: PC Gamer Article
Now here are my thoughts:
It's not that MMO's "don't work" in the United States, it's the complete lack of innovation that cause gamers in the United States, who are all more than familiar with having too much of one thing, to lose interest quickly if something does not feature anything that they had not already gotten. I would say it's probably one of the major reasons as to why World of Warcraft has been so successful, and Everquest before that. They were the games that had set industry standards by being innovative titles on their own.
Now, MMORPGs are held to the same standards that World of Warcraft, itself, has set and, unfortunately, if they don't exceed, or even meet, these standards they're doomed to fail. Once again, this is due to developers refusing to innovate. They all want to play it safe, believing that doing so will guarantee at least moderate success -- and then being absolutely shocked that their game is not as successful as they had hoped.
This was a problem with Star Wars: The Old Republic. It was a fresh image, it had a lot of promises, and it featured a player-specific story arc that each class dives into from the very beginning -- unfortunately, that was all it offered. The game played and felt too much like World of Warcraft, and it bled in subscriptions as players who were tired of the same formula left the game. Only true die-hards played the game, but it wasn't enough to sustain profit. They've seen more success from going free-to-play, but I haven't personally played since a few months after release, so I wouldn't know right now.
Then there's Age of Conan, and Warhammer: Age of Reckoning. Everyone thought that these games would seem some modicum of success, and had a lot going for them. Age of Conan brought to the table a more player-driven experience rather than keeping everything on rails, and Warhammer featured massive PvP environments -- then when the games released, they failed to meet the expectations. Warhammer felt too much like World of Warcraft (although, admittedly, their PvP was something to envy). I don't know what happened to Age of Conan, quite honestly; I just know that it wasn't what a lot of its players were hoping for.
Now we come to the last few years, and out of all of the games that were released recently, Guild Wars 2 was the only one that has, so far, seen its fair share of success. It truely aspired to innovate, revamping many different gameplay mechanics that are, currently, very outdated. It improved movement controls to make everything based on reflex rather than mashing buttons. It did away with the "holy trinity" of MMOs (Tanks, Healers, and Damage Dealers) that has "plagued" the industry for the past decade. It's obvious, however, that the game focuses more on PvP, as it offers very little in terms of PvE end-game content, but the fact remains that Guild Wars 2 has tried, and so far has been very successful with its "buy-to-play" formula.
So it's not that MMOs don't succeed in the US. If there were any thought put into gameplay design beyond what has already been tried and true, we would have seen more successful MMOs in the recent years. Developers just have
to strive to innovate, to bring new things to the table that would bring players in, and keep them. Too much of the same thing will drive players away. (Though this is only true in some cases...)