Why characters in short stories differ from characters in novels

Short stories tend to be about outsiders and eccentrics. The lead characters and narrators have very little space in which to establish their identities, and as a result they tend to be have extreme behaviors and distinctive traits. The scope of the narrative is small and tight, and therefore short stories tend to have few characters - which also means that stories often involve social isolates. Can you imagine an Austen or a Dickens character in a short story? Can you imagine a Raymond Carver character in a novel? This short story phenomenon parallels the traditional American v British dichotomy: Americans writing about outsiders who "head out for the territories" and British writing about characters yearning for inclusion in society (has much to do with class culture v democracy). There are exceptions to every premise, too: Dostoyevsky certainly writes novels about loners and eccentrics; Updike and Beattie certainly write stories with complex, novel-like social structures. Reading a bit more in Aleksandar Hemon's Best European Fiction 2011, struck by all these observations about the short story, with the added element that European writers, judging from this anthology (or from Hemon's personal tastes) are much more drawn to experiment in form and to narrative ambiguity than are American writers. Frank Berry's Doctor Sot a good example, and a good story: alcoholic doctor drawn to a hippie-type settlement on the outskirts of his town, spends the night there while his jovial wife, back at home, does - something? Not clear even on re-reading what exactly she does: howls at the moon? Who knows? But the story is poignant and also a bit decrepit, like just about every other one I read in this anthology.