It certainly varies but speaking in generalities, what attracts new players, is being able to instantly jump into a game and make sense of it, feel like they have some competency or skill that they can further refine or a connection to what is going on… think of Luke Skywalker doing the trench run at the end of star wars, the farm boy being out of his element but still being able to pull out a clutch move or save that everyone is like “wow great job kid”… thats what gets players hooked. The feeling that “hey, maybe I am good at this, I should keep playing and trying to get better” or “I am dominating this is awesome”.
To put it in wow context, there are so many trap talents and gotchas built into the game again, [some of] the specs are so convoluted that they don’t even feel polished until you get higher ilvls to get the haste\procs needed and the game systems are so complicated you need in depth guides (even the advanced players) just to navigate them, its all extremely off putting to new players (I have tried to bring a few back/introduce new ones… I currently have one recruit a friend active). The amount of required knowledge (because all the Devs have that knowledge and are clearly biased by it) is astronomical.
Blizzard has designed content so that only M+, raiding or PVP matters (and some small minor world content like sparks/professions - it certainly has potential if they let it shine a bit more in outdoor content). I think everyone agrees PVP is completely out unless you have a FPS style convert gamer that wants the competition… and even then once they realise just how outgunned they are, they don’t want to make the climb or even invest in getting good.
Raiding has been a main stay but most gamers these days do not build their life around gaming, its a background / Time sink activity that they want to drop in/out of on a whim not schedule life around “mon/wed is raid night”. Raiding becomes more burdensome as PCs/AI manage our logistics less people want to engage in that kind of role. Talk to any guild master and ask them how they like dealing with people’s drama vs just being able to play the game.
Then there is M+… which you can refer to any other thread on here about what that is toxic.
TL;DR
I been playing wow almost 20 years with a lot of different players and in a lot of different guilds, I could write a thesis on this.