There was a game that was closer to trying that: Rift. It ended up on a failure trajectory because the end game was too hard for most who tried it. Hammerknell was a blocker for most guilds in original Rift, and the next expansion just doubled down on that failure. After that there was no saving the game.
Another fun Ghostcrawler tweet from 2013:
https://twitter.com/Ghostcrawler/sta...29787176140800
"people who want challenging content, which historically has never been a huge percentage of our players"