The lesson is simply this: you just have to recognise that, no matter how much weight you put behind it and how much you tart it up,sometimes a story just doesn’t bloody work, and you have to take it behind the stables and shoot it through the head. No writer is perfect. We all have dead bodies to our names.
The corpse gets thrown in the Loose Ideas folder, where one day it will doubtless be cannibalised for its more interesting/less ripoffy parts and interpolated into something new and better. Storage of corpses is important. As in life, you never know when bits of them will come in handy.