Early MMOs were borderline sadistic. EverQuest, for example, had amazingly awful class balance, forced grouping, experience loss on death (including de-leveling), corpse runs, and painfully slow, mechanistic gameplay that demanded nearly flawless gameplay. Huge sections of the world were functionally off limits without a group. And random roaming mobs under your level could still kill you. And the game didn't have built-in maps or 87 websites devoted to data mining all the newest information before it was even live.

All that user unfriendliness had the side effect of creating a fundamentally different kind of social experience from what exists today. The world felt big and dangerous. There was a sense of wonder and exploration and necessary togetherness. There was community, and people had reputations. EQ was also considered a runaway success with a peak of 500,000 subscribers.

Each successive generation of MMO made the gameplay more refined and accessible, which lead to more popularity and higher subscription numbers. But the side effect is that they destroyed the adventure aspect of the genre. That sense of shared frustration, slow pace, and danger helped bring people together and created online identities with some level of persistence. Now you can solo 97% of the content. We have dungeon match making (with people from different servers) and built in maps and macros for skill rotations and everyone gets their loot.

This isn't too day all changes since EQ are bad. But WoW is basically a Blizzard-themed skinner box. It set a new standard for polish, accessibility, and financial success. We've seen little wider but iterations on the WoW formulas since it's release. And people regularly predict its death despite it being 10-20 times the size of EQ at its peak.