But then, few books are great in every aspect (though I won't deny there are some that certainly come closer to that ideal than Austen's).

I glanced through the first few chapters of P&P on Project Gutenberg just now, and to the extent that those can be considered representative (not very), the conclusion is that much of Austen's writing is simply dialogue, and her dialogue is good, as I'm sure you'll agree. Of the rest, a good part is taken up by witty or ironic touches (which I at least find amusing). The descriptive prose is very simple indeed, but why should that bother us? It's the characters and the dialogue that make the novels such classics, and the ironic comments like the famous "truth universally acknowledged". And of course a good part of Austen's reputation is simply that she wrote those books when she did, and that she was already a classic to the Victorians. If there are other English writers who have written novels comparable to Austen's prior to 1820, they certainly haven't stood the test of time.