I'm also a younger millennial, but I think this is just somewhat attributed to having enough bad experiences with PVP games, and that's fine.
The fact you are playing against other sentient, strategizing, sometimes malicious, but sometimes naively innocent, unpredictable, biological machines is just something you can't really find in single player games.
There's all kinds of pitfalls where you either take things too seriously, too personally, or just meet a ton of assholes in too short a time. It's a bit like life itself. It's got the highest highs, and the lowest lows.
Single player games are simply a lot more consistent in avoiding the lows, but at the cost of never being able to reach those highest highs of knowing you did so well against actual human beings, opponents you can consider your peer or even smarter than you. No single player AI opponent can match that. They usually never play by the same rules as you do, or lack the same weaknesses you do.
But since we remember the lows much more vividly, everyone remembers PVP games as being miserable. Yet we keep playing, because deep down we're hoping to get that high again. I think it's fine to let people enjoy that. But it might not be for everyone.