The problem is twofold:
1: In their rush to streamline everything they kinda removed any real reason to talk to anyone outside of high-tier raiding and PvP (and even then you jump on Discord if you’re serious.
You don’t need to talk to people to get into dungeons because of LFG.
You don’t need to ask people to make you profession gear or weapons because you get gear extremely fast, you have heirlooms to level up with and as soon as you hit 120 you can hit 370+ without ever touching a single dungeon or raid.
You don’t need to ask people to group up to take down a difficult quest mob because everything scales to your level and nothing is a challenge anymore (and for higher level content you have the LFG button).
Nobody talks because there’s no need to do so anymore, you just log in, do some PvE content with some bots, do your solo content and then log out.
2: Society itself has changed dramatically over the last 10 or so years, even outside of a virtual environment we’ve become more and more reclusive and seemingly reluctant to communicate, either due to people preferring to communicate online and within our own social groups or because they’re wary of talking to others for fear of offending them and getting in trouble (thanks social justice).
Communities in general have massively changed, but with WoW it isn’t helped by this lack of reason to communicate with others for the vast majority of the game.