Yeah. Short Stories, Not.
Just look at TV and film. So much of our at-home video watching is now cable TV drama series with season-long story arcs. And the most successful films are franchises which carry relationships and storylines over from one film to another (The Matrix, LOTR, the Hobbit, Avengers -- and pretty much all the superhero films.) Busy, attention-strapped audiences don't want shorter stories, they want longer ones.
In fact, right now when my attention span is at its lowest point since grade school (because of ongoing CFS), I crave novel series, not just single-shot novels, and have NO attention at all for short stories.
And I think it's because *any* new fictional world we give ourselves to requires an initial investment of energy and attention to orient ourselves in that world and with those characters. Once we've done that, it's basically easier to stay in that world, with those characters, over multiple stories and arcs, than to pull out, reorient, and invest in something new. Short stories are exhausting to me right now, and I won't have them.
By the way, I think there's a synergy between audiences wanting longer relationships with filmic worlds and characters than is available in a single film, and the transference of comic book stories to film franchises. Namely that comics mastered the art of telling stories containable in limited episodes, but that fit into longer arcs, and that's what the TV world had to do following Buffy, and what the film world now has to do, now that audiences have clearly spoken on this issue.