100% this. I was kind of oblivious to the young people only on mobile thing until more recently when I started, out of boredom dabbling with pubg mobile. the amount of little high pitched voice kiddos on there, randomly getting in an argument with their parents on an open mic mid game is absurd. (that and indians playing with cars honking at them mid traffic but thats another issue)
But look at pubg pc or other games just on PC and it's definitely an older demographic in comparison. youngest maybe being 20'ish. but more older than younger for sure.
At least with PC gaming, or even console gaming you have to be in a somewhat dedicated area for it. which I think the younger age just can't do. Be it the ADHD, or whatever it is keeping them from sitting still long enough to enjoy a game on a pc/console. They have to have that option to either shut it off at a moments notice or move around for whatever reason. and MMO's just cant offer that capability, no matter how much they water down dungeons/raids into shorter and more pointless experiences.
And on top of that, I feel those failed attempts to do that to the content just promotes shit behavior on top of it, on multiple levels. From refusing to communicate, or to not give a damn about it, to even rejecting the idea of it flat out. I've been kicked from LFG shit in the past for simply trying to have a conversation during a boring, repetative dungeon i was just doing for my daily. Even if I was doing more than 50% of the groups total damage.