That's actually a very snobbish attitude, part of the whole "genre fiction is not real literature" fallacy. One can read P&P a thousand times and still get nothing but a cute regency romance; one can write Austen fanfiction for ages and come up with nothing but fluffy sacharine pieces or nearly-plotless smut. Austen is a great writer, but whether or not her work provides insight into anything depends on the reader, not the material. And one can find insight in many works that are not so "literary".
There are many insightful, profound fan fiction stories based on sf tv-shows and fantasy novels. What may give the impression that the Austen fandom is more serious-minded is than other fandoms attract a larger number of fans who are in it for the "cool" factor; it happens with Austen too (like after the 2005 film), but to a much lesser degree. Age is also an issue; I think Austen fans are more mature (as opposed to, say, Harry Potter, that is after all children's/teen's fantasy) and that reflects on the fan fiction.
There are many insightful, profound fan fiction stories based on sf tv-shows and fantasy novels. What may give the impression that the Austen fandom is more serious-minded is than other fandoms attract a larger number of fans who are in it for the "cool" factor; it happens with Austen too (like after the 2005 film), but to a much lesser degree. Age is also an issue; I think Austen fans are more mature (as opposed to, say, Harry Potter, that is after all children's/teen's fantasy) and that reflects on the fan fiction.