There are other long running MMORPGs that are worth mentioning like RuneScape (https://en.wikipedia.org/wiki/RuneScape). A few years ago they realized they changed the game so much that they decided to 'restore a backup' from the good old times and launch it as 'Old School RuneScape'. If I'm not mistaken this retro version has more users than the 'main version', currently called RuneScape3. This game has a documentary on youtube and such. The main problem I found about being a 'long lived running MMORPGs' is that although the game still exists, the company was bought twice as far as I am concerned, and that changes a lot of things in a game, specially regarding to monetization. For example adding some gambling features and not standing much for ethics inside the game (e.g., bug exploitation) as a measure to keep paying customers. In the documentary the founder & ceo (Andrew) explicitly regret selling the company after seeing how the game (or at least some part of it) turned out to be.