Some stories take longer than others.
I recently (well, fairly recently) "finished" two stories that I'd been working on for probably more than 10 years (though "working on" isn't really accurate; years went by without touching them). One story found a home; the other is still an orphan.
The former was recently published in kill author. It takes place on a plane. In May I flew to New York. I hadn't thought about the story in a long time, but as I settled in for the long flight, it came to mind. I had a few ideas, jotted down some lines. More important, I finally figured out the beginning and ending, both of which had always eluded me. Nothing ever felt right. And the entire story never felt done. Something was wrong. Something was missing.
Here's a well-known quote from a Paris Review interview with Ernest Hemingway:
Interviewer: How much rewriting do you do?
Hemingway: It depends. I rewrote the ending of Farewell to Arms, the last page of it, 39 times before I was satisfied.
Interviewer: Was there some technical problem there? What was it that had stumped you?
Hemingway: Getting the words right.
Getting the words right. So simple and yet not so simple.
I've started and finished many other stories while these two other stories were "in progress."
As a writer, sometimes you have to be patient. The story takes a while to be told. And that's okay. And I've found that the ones that take the longest are also usually the most satisfying.