Though my first published story hasn't earned as much as that one, it is my highest earning story and that was also an idea that just struck out of the blue. I remember writing it quickly one wet Sunday afternoon and did very little editing before sending it straight off to Pony magazine. They bought it. All the stories I had lavished huge amounts of time and attention on, the stories I had had critqued and had subsequently tweaked in line with comments received, the stories I really cared about, came back every time! They still do.
However, though the Pony story was my highest earner, my most successful piece of writing to date isn't a story; it's a haiku. It has earned me precisely nothing, but in terms of being read by most people, it's a clear winner.
I originally wrote it in a creative writing class in which the tutor was trying to teach us how to write haiku. It is therefore one of the first haiku I ever wrote (probably my second or third attempt), but later it won an online haiku competition and someone must have remembered it from there because a couple of years later, I was asked if it could be included in Creative Writing: A workbook with readings published by the Open University, which is the set book on their second level 60 point creative writing course.
I don't know what the moral of this story is. The other stories I've sold were the result of hard work and multiple revisions and comments from critique groups, so I'm not saying that you shouldn't apply yourself to stories and I'm certainly not saying that you should just sit around waiting for inspiration to strike.
I suppose one thing it does show is that caring passionately about a story isn't any guarantee of its quality and/or saleability. I have had students complain that they can't write to prompts because they feel that they need to have some deep connection with the subject matter, but if I'd taken that approach, my cat haiku would never have been written. I also wouldn't have written the story I sold to Andromeda Spaceways Inflight Magazine either because the first version of that was written in response to a silly game on a Usenet group. However, the story about fairies borrowing the iron griddle was an attempt to express things I felt strongly about, so caring deeply doesn't rule out success either.
In the end, I think it just goes to show that it's difficult for the writer to gauge what will click with the reader and what won't.