Legitimate fanfic

It seems to be fine to use the characters in books by dead authors to write novels, publish them as original works and make money out of them. The latest are Sebastian Faulkes writing a Jeeves story and Anthony Horowitz writing a Moriarty story. In these cases the writers have the permission of the late authors' estates, but what about Jane Austen and Charlotte Bronte? to name just a couple of authors whose works have had sequels written by modern authors. I tend to avoid these novels because they are usually not as good as the originals and I think authors should not make money using other writers' original characters. Anyway, when published authors write what amounts to authorised fanfic, can writers blame fans for writing fanfic for pleasure and to share without profit?