I'm sure there's a questionably witty name for it on TVTropes if I could be bothered to look for it. I just call it "status quo ex machina." It seems to occur with great frequency in cheesy movies and Crichtonesque airport novels: if the main plot concerns some sort of fantastic discovery or hidden treasure, then that extraordinary element must be completely, unambiguously destroyed and the ground salted before the story can end.
We're all familiar with the related scenario from TV, where the status quo must be reinstated if the series is to continue. That million-dollar inheritance won't be there by the end of the episode; Gilligan isn't ever going to get off that island. But the same scenario seems weird and pointless in apparently autonomous movies and novels.
This problem struck me when I recently encountered a couple media riffs on the basic "Treasure Island" plot. Some years ago, Disney produced an animated feature adaptation of "Treasure Island"-- IN SPACE! Treasure Planet was an almost point-for-point retelling of Stevenson's novel, only with rockets attached. There was one interesting departure, though; as you may recall, at the end of Treasure Island, the characters actually keep the treasure.
Now, this seems like a natural, sensible ending for a treasure-hunt story. But for some reason it has fallen out of favor. Instead, in Treasure Planet, the entire vast fortune is snatched away at the last second when the planet explodes, leaving only just enough treasure so that the characters can pay back the cost of the adventure.
This same basic scenario crops up in Riptide (the novel by Bill Preston and Lee Child, not the late-'80s TV show starring geeky character actor Thom Bray and his wacky pet robot). The novel is a sort of dubious techno-thriller version of Treasure Island, with all the cheesiness that implies; but it is nonetheless fairly readable with an interesting hook. Then at the end, the treasure is snatched away by the dumbest device imaginable:
Spoiler (mouseover to read):
it seems that the pirates just happened to bury their treasure right over the largest, nigh-bottomless abyssal cavern imaginable, so that when the treasure hunters pick up a box of treasure, it pulls out a keystone and the entire treasure is literally flushed away into the earth's crust.
Now there is no good reason why this has to happen. It is like a reflex, and you see it again and again in this sort of adventure story. Michael Crichton pulls it at least twice, in Congo (lost city of fabulous riches and monstrous hybrid gorillas, discovered just in time to be destroyed by a volcano), and Jurassic Park (in his original novel, the dinosaurs are all killed when the Air Force carpet-bombs the island).
Stephen King was another prominent exploder, at least early in his career. From The Shining through It, practically every story he wrote had to explode at the end, often for no apparent reason at all. I don't know what he's doing lately, or if he's managed to shake the exploding. Actually I did pick up Cell the other day. That was extremely bad. And there was an explosion at the end. So apparently not.
Why is there this seeming need to ultimately destroy all traces of whatever fantastic subject your story happened to be about? I fully appreciate the basic need to have a big explosion at the end of your summer movie, but this seems like something more. Why does it happen in novels? Are they, perhaps, just using the most 'movie-like' plot elements in the hopes that Hollywood will come calling? If so, Jurassic Park should serve as a lesson: Crichton blew it up in his novel, but Spielberg knew better.
In summary, there seem to be two related principles at work:
1. fantastic story hooks cannot be allowed to survive the story's end; and
2. characters cannot be seen to profit in any way from their adventures, excluding personal relationships; the guy gets the girl, the teenager is reconciled with the parent, but none of them get any other reward apart from just getting out alive.
Is this really a phenomenon, or am I just imagining it? I was inspired to post this thread after reading a fascinating "lost world" adventure novel. Then at the end, the lost world gets blown up TWICE.
At the same time.