I understand that 'kill the bad guys and take their stuff' can be usefully used as a core story of D&D, and I'm sure I read an article on the WotC site saying as much.
However, I think that the original core story of D&D was dungeon exploration.
case 1: the basic setup has a DM with perfect knowledge of a situation and 1 or more players who don't know the situation and explore the dungeon (most commonly) or situation/mystery (gradually became more common) in order to have fun 'resolving' it.
case 2: when Gary Gygax DMed and adventure for some lucky mods at Gencon this year, IIRC it was largely about exploration (Piratecat or someone else who was there might be able to comment on that).
"kill the bad guys and take their stuff" has a thriving internet meme behind it, for very good reasons, but I'd never heard D&D described that way in the pre-internet days.
Might be worth thinking about.
Cheers