I am obsessing on fictional worlds right now. How worlds draw us in and why, how, and what makes that so enticing. It is fascinating really. And it has really got me thinking about how escapism makes us want to remain a part of that game world, even when the game technically is over.
And it is worst with linear games. Especially games that have really fetching universes have that bitter taste once they are done. When the story is over, you are evicted from that universe. Sure, you can play the game again. But it will be more or less the same things occuring - at least not anything dramatically different. That reduces the escapism to a mere replay, like rereading a book or seeing a movie twice. It is not really as enchanting, and the world loses its edge, its tenability, at least after a couple of times.
Open world games face much of the same issues. Because even though they allow a lot of freedom and appear to provide you with a story you helped create, we are still forced down a general path. We notice that especially when playing them again.
BUT, open world games have the perk that they often allow us to remain in the world even when the main storyline is over. The problem is that the world then remains the same, more or less. And anything occuring is repetitive. So the world will eventually feel pointless. After all, there's not a lot to do but to do weird things like kicking chickens to get the achievements you're missing. Or collecting all the collectibles you couldn't bother picking up on your way through the first time.
The MMO I think, has found a way to allow everyone to remain in a (more or less) dynamic, "real" world. And this also means people usually feel more ready to commit to the game. I'd never thought about it, but when a friend told me, it really got me thinking. Because the things they do in an MMO will always be there. If they level up -- they are never going to be demoted to a lower level again. And the game is never going to be "over", so they can always keep playing.
So the MMO worlds are more stable, they change, but will never take away your investments in time or effort unless you are exploiting the game or they are making changes that nerf your items or class.
So, the MMO worlds keep changing, new content is added, what lacks in content is fulfilled by the social aspects. All in all, the MMO world never "ends" as such. It wont kick you out and tell you "The Story Is Over!"
That doesn't mean MMO's have got it all right. A lot of MMO worlds lack possibilites and diversity, encourage griefing and grinding. All in all it is just the idea of the universe never ending that I think is one of their strengths.
A plausible universe, a world with its own history and culture, its own flaws, its own tears and its own laughter - it's a good place to immerse. A good place to play and learn and explore and experience. Game worlds have the interactivity that books and movies can't provide (no, duuh). And it's extraordinary, like magic. We don't know what will happen when doing this, or how people will react when doing that. It is truly unique, and very powerful.