Bartle's four quadrants is standard in gamification practise. Your assessment of its validity probably tracks with how effective you feel gamification can be in altering human behavior ;)

The more interesting modern use case is when people say: "there's this game on my phone I play a lot that helps me with my anxiety." And it's usually something trivial like a free Puzzle Bobble clone that was developed in a week at zero-budget. But for that player, its a lifeline, a coping mechanism.

That's very interesting to me. What is it about this gameplay mechanic that relieves stress? It can't just be escape. To me it seems it has to tap into something more intrinsic than archetypal "hunter-gatherer" era categories.