The need to communicate in order to succeed is at least one very, very large factor. Today in the WoW of accessibility, other players are more often than not a hindrance. No need to group up for anything in the world other than world bosses, no need to communicate in any group content unless it's high level m+ or Heroic raid. People that only run dungeons and LFR find themselves in a quiet "community" that only communicates when someones makes a mistake, making it toxic, unforgiving and excluding.
One of the results of all this accessibility (read: lack of challenging content outside of organized raids) is that it's harder to form friendships with players. I have little doubt a lot of people can relate to that, they've made less and less new friends the older the game got. I still have people on my friendslist from the times we were fighting through something as 'trivial' as Shattered Halls heroic. Because you couldn't just zerg it. Dungeons wasn't a mere side-thing you pressed a button and then got teleported to, put together with 4 randoms you'll never see again.
But sure, on paper all this accessibility is positive, larger portions of people do "high end" content, less time is wasted on doing "things you don't want" like looking for groups in chat, traveling to the dungeon, getting keys or attunements. It's just "now now now" coupled with low difficulty. It kills the enjoyment but most people can't figure out WHY.