I kept waiting for the punchline but it just kept digging in the same vein. I'm not sure what else there is to gain from the text beyond the core gimmick.
From your choice of words and the fact that you wrote, I would gather that the story didn't leave you indifferent. So it achieved something.
What do you understand as "gimmick" and how could a "punchline" for that story look like for you?
I guess overall I have no complaints except that it could have been shorter. It seemed like it was building to a conclusion that never coalesced, which is okay for short fiction, but this one was sorta a slog.