It feels like at some point comics became more about the hero's internal monologue and psychological issues. Kind of like a 30's pulp detective with some modern pop psychology thrown in. Villains just became a bit of background color while the story was about that inner monologue. I think it may have reached its height right around the Buffy era. Buffy had a lot of dusting vamps while the real story was about things like her angsting about being pulled back into the miserable life of a Slayer.
It reached its height then, but then it just kept on at that height.