>>724954769 (OP)
An MMO just is not going to capture imaginations like they did when wow came out.
Wow marketed itself as an entire world, far beyond a game. It was presented as basically inexhaustible, so vast a game that your character was a major part of your life and identity. There was no promise of "endgame" in wow marketing because it was almost acting like there was no end, no point where you've seen pretty much everything and don't need to really explore anymore and are just grinding relatively a small amount of much more difficult remaining content.
That sales pitch depended on an era where the frontiers of what video games are was expanding at a rapid and unpredictable rate, not the diminishing return incremental situation we have now where the biggest innovation or expansion in capability is raytracing.
You needed an era where a game could be advertised as a whole world, and people were like "well I don't know, video games get so much better every year, maybe it is like a whole world" and can buy into that sales pitch the way they did back then. Then of course long term players run into the boundaries of it, there's a level cap, its really big for a video but nowhere near realistically big, but if they've stuck around that long they clearly really like it, and its world-y enough that they generally don't feel dissatisfied or gipped. But the stratospheric popularlity it enjoyed for a few years back then did depend on being able to sell that initial fantasy.