Times have changed since 2004 or even the 1990s when everquest came out. Kids and people in general have shorter attention spans and want instant gratification which social media provides whenever you get that blue or red dot on your notifications. People are so desperate to seek approval and attention from masses of strangers and be told how pretty or funny they are.

MMORPGs have the consensus that you have to wait till endgame or a certain level for it to be "good" usually when you unlock raids and etc. Apart from that MMORPGs are an endless grind of collect X, defeat x, talk to x. Which sooner or later gets boring.

Coupled with the fact that MMORPGs dont provide full voice acting, may have outdated graphics and less cinematic sequences/events. Whereas a single player game will have all of these.

Lastly MMORPGs are a product of their time. In the early 2000s for example kids and teenagers had little else to do or to distract them rather than Scheduled TV Programming, Playing Outside and browsing internet forums and etc. Therefore MMORPGs were a fun alternative, a competitive game you could play with your friends.

But then Online Streaming like Netflix, Social Media, Better console games came along and MMORPGs weren't really needed anymore as most Console Games nowadays provide a way for you to play with friends or with strangers on online modes. And they weren't repetitive like an MMORPG

People tend to forget MMORPG has the words "Massive Multiplayer" in it. They're not intended to be played as a single player game. You can but you'll get bored quickly. However people in MMORPGs nowadays are more anti social and arent concerned in meeting new players or talking with others outside their immediate friends. If you've ever been in a low level WoW dungeon 99% of groups are deadpan silent, you're just expected to shut up and know your role and different PvE terminology.

This leads to a circle jerk of most MMORPGs being solely comprised of "l33t" veterans which make up a small minority.