Let me find a post I made on another forum for a different single player game.
A story driven game that has a beginning and ending can not be an online game and maintain itself. The only reason people play online games is that there is always ways to improve your character. Don't get me wrong, I do like my online games, but I don't play them for a deep and rich story. It's all about the gameplay, gaining loot, getting stronger and finding new stuff. A story always has a beginning and an ending. If an online story driven game has an ending, what's the point of continuing to play if you beat the story? Unless you are thinking of a Soap game. Where every month or so new story content is unlocked and you will play more story. However it will never end.
That could be an idea, but it is very costly in resources and I think people will need to pay a subscription for it to work otherwise the company goes bankrupt. Unless you make it free with micro transactions to unlock more story/lore, which is unfair to begin with.