Great article. This is exactly what happened to me with the last story I posted. It languished in my docs for nearly three years before I dusted it off. I'm still not completely satisfied with it, however, during the finishing process the writing led to ideas for two subsequent stories.
The one I'm currently working on is far better (imho). I think I needed to work through the first story in order to get to where I am in the overall story arc.
Three years isn't too bad when the end result will be three stories in the series. Who knows, it may be even more eventually. An author never knows what secondary characters will start yelling inside their brains for a story of their own!