Short stories have largely vanished as a commercial form, with one significant exception. Science fiction has kept its short fiction market alive, and the genre depends on it more than readers of novels realise.
The genre grew up in magazines
Science fiction established itself in periodicals before it established itself in books. Writers were paid by the word, published monthly, and read by an audience that followed the magazine rather than the author.
That inheritance shaped the genre's habits: an appetite for premises, tolerance for the unfamiliar, and a readership comfortable with unknown names.
Those habits persisted after the book trade became the main commercial channel, and they are visible in how the genre still discusses itself.
Anthologies extended the same arrangement into book form, gathering stories that had already been published and paying for them a second time.
A short story tests an idea cheaply
Speculative fiction runs on premises, and not every premise survives contact with a full novel. A short story lets an author find out in a few thousand words instead of a year.
Many novels in the genre began as stories that proved to have more in them, and the expansion happens after the idea has already been shown to work.
Ideas that do not expand still have somewhere to be published, which is not true in most of fiction.
It functions as a visible apprenticeship
Selling to a recognised magazine is an achievement editors and agents can read at a glance. Publication history in short fiction is a credential when a first novel is submitted.
Editors of these magazines read enormous volumes of unsolicited work, which makes them one of the few remaining routes into publishing that does not require an introduction.
The path is slow and pays little, but it is open, and the genre's newer novelists frequently arrive through it.
Awards keep the form visible
Science fiction's major awards carry categories for short fiction alongside novels, which sustains attention on work that would otherwise be commercially invisible.
Award recognition drives anthology reprints, and anthologies pay again for the same story, improving the economics of writing one.
A shortlisting is also read by editors as evidence, which converts an award nomination into a professional asset rather than a decoration.
Why it survives here and nowhere else
The genre retains a community that reads collectively, discusses at conventions and treats short fiction as a normal part of following the field.
Where that community structure does not exist, short fiction has no distribution and no audience of its own, and the form has correspondingly disappeared.