It should be a question: How do we get those old habits to die? The habit in this case is a holdover from my last campaign, which may have only been a few months ago, but as it was conducted under the modern D&D mindset, it really is a world away from what I'm trying to do now (and not just because I'm trying to get to Mongo).
Oh, right, the habit: I have a habit of treating the player characters as protagonists in a story that I'm trying to tell, with the players apparently there just to interfere with the progress of the narrative by flubbing their die rolls and not having enough hit points to survive my hot streaks of max damage. That's an exaggeration--I don't actually sit down with a story ready to inflict on the players, but story threads stemming from character backstory occur to me as we play, and they drive the events in the game world.
The problem with this in old-school play--or any play, I suppose, where the characters haven't got "plot immunity"--is that the characters are going to die. A lot. If they're no longer around to carry your plot threads what happens to your game?
It fizzles, stumbles, stops. Or, that's what happened last night. So what I have to figure out now is how we can think about the PCs and their roles in the game so that their deaths don't hollow out the whole affair--so that there is something left behind when a character's motivation is lost.
I think the solution is to keep it simple: the wilderness is dotted with ruins that hide unknown riches, free for the taking of any brave soul who can discover their hiding places and overcome their horrid, unnatural guardians. The dungeons are like mountains calling to mountain climbers: someone is going to plunder them just because they're there.
Well, I think the promise of untold riches is a way better motivator than wanting to get to the top of a mountain just to challenge yourself. And that's why I play pen-and-paper games.