The good thing about science fiction/fantasy/horror is that there are still a dozen good short fiction periodicals—good meaning that they pay writers (usually between five and ten cents a word), they have an audience beyond their pool of regular submitters (a few thousand readers), and they have reputations (stories they publish regularly appear on award shortlists in the field). There are also about a dozen good anthologies a year that are open-call submissions, and six or seven chances for reprints in best-of annuals.
This allows a writer who likes short fiction to keep busy. I’m rounding out the year with a new story, “The Phylactery”, in the latest issue of Apex Magazine. Apex, like many magazines these days, is online and generates revenue via ebook sales, Patreon, anthologizing its content, and the like. It also runs a small press for novels and collections. “The Phylactery” goes online on the fifteenth, but the entire issue can be purchased early as a $2.99 ebook.
There are strong commercial pressures that encourage writers and MFA students both to focus on novels, but a regular stream of short fiction can both pay (some) bills, and help build a reputation, so I’m going to keep recommending that our students get into the field and play some short fiction ball. At the very least, you’ll fail at it and thus improve faster.