Story suffers most when the reader and the writer are steered to expect certainty of outcome.
To the degree that reader or writer engages the project with certainty, you can almost hear the story in question complaining how its true nature is being stolen from it, replaced with one or more cultural lies, repackaging propaganda as the story the reader thought to read and the writer started out to write.
In one of the many ironies attached to the writing, reading, and teaching of story, the quality of certainty is inevitably swept under the rug of motivation and, thus, character, buried, as it were in the haze of outcome.
Readers turn to story as a respite from reality, not a conversion of it from bad news or provocative commentary to the inevitability of amor vincit omnia, the early bird catching the worm, and that most uncertain certainty of all wherein doing the same thing over and over in the same way is guaranteed to produce the outcome of success.
More than any other cultural certainty, If at first you don't succeed...etc is the closest thing to calling a mulligan on Reality. Maybe the answer is to reexamine the process. As you recall, tungsten was not by any means the first filament Edison tried to produce the then miraculous incandescent light bulb.
To the degree that reader and writer each bring to the reading/writing process the totality of effect their culture has had on them, each must learn a grammar of Reality as well as the grammar of story. This becomes prologue to how certainty of outcome must become objectified, brought to the attention of the reader and the writer, then sent out on a quest for vision that will give the outcome endings such as those given us by the likes of D.H. Lawrence, Katherine Mansfield, Louise Erdrich, Elmore Leonard, and Deborah Eisenberg to their short stories.
You could well add to the list; James Joyce, for example, John Steinbeck, John O'Hara, and JCO, for immediate instance. Any and all of these had the sorts of effects in the outcomes to the characters in their stories that had immediate, visceral effects on you. Most of those effects were unsettling.
By all means, you wish your stories to have that effect, and when you review half- and three-quarter-written narratives after having left them in the stock pot to simmer, and then, when they don't have that effect, you look for some clue to reshape them.
Of all those writers you mentioned, Leonard and O'Hara are the two you admire for their ability to link their disturbing outcomes with humor, and you often find yourself, in those moments between wakefulness and sleep, trying to imagine the outcome of some of Lawrence's stories were his outcomes more centered in humor.
Which reminds you of two things, the short stories of Ring Lardner and the fact of you having set such a high bar for yourself. The writers you most admire have led you to that strange, disassociated land between certainty of outcome and the greater certainty where Marvell's deserts of vast eternity await us with the certainty of their ambiguity.