"Simulationism" - in the sense that the players of a RPG should have no aspiration beyond experiencing the fiction, as some combination of mechanics and GM narration present it to them - seems to have become a predominant orientation in the early-to-mid 1980s, and to have continued, perhaps in fluctuating degrees, since then. Classic D&D was not this sort of game: the aspiration of a player of (say) Tomb of Horrors or Gygax's Castle Greyhawk is to beat the dungeon, and thereby earn treasure and thus experience points. The fiction is a means to an end, not an end in itself.