Emerging trends are slippery things. Some are driven by a demand for whatever is trending, others are an attempt to fill a demand with a substitute. I am reminded that heroine was introduced to the Western world as a substitute of morphine, and I worry that some other unfortunate substitutions might have bad results as well. After all, these things aren't thought out, except my marketers, whose only criteria, by definition, is that it sell.
An article on BBC discusses continuation literature, which is basically the idea that there is no reason a popular writer shouldn't continue producing new books simply because they are dead. In a way, this is a bit like fan fiction. You put known and beloved characters in new situations and enjoy the result. The difficulties I have with this are twofold: first, the books are chained to a static world. The living writer was free to change things, kill off characters or change their nature if that suited them. The best another writer, a good and well-intentioned writer can do, is stick with the establish characters.
The second issue is that it tends to make a mockery of the whole idea of being a writer. If I've never heard of a book, I might buy it based on who wrote it. I love series, but if I am new to Miss Marple, and get hooked, and see there are fifteen in the series, I will be rather pissed if halfway through I find they are written by someone else. And author isn't a brand, folks (I do know it is popular to think so) but a voice. A unique voice and another writer, regardless of skill isn't going to write the same. I love Sherlock Holmes but should point out that the Holmes of Conan Doyle is not the Holmes of Laurie King. Personally I love Laurie King's approach of continuing the saga, extending a character but in a new and different way. And there is no pretense that it has much to do with Doyle.
If writing books by a dead person is wonderful, why not extend it. I rather like the books of Milan Kundera and Haruki Murakami and wouldn't mind writing one in the style of each. Hell, why don't we swap around? They can write my next two books and I'll write one under each of their names? To keep things fair, seeing as they have a few more fans than I, they'll probably want the royalties collected for the book under their names, so we need to chat. I'm good with that. Milan, Haruki, give me a call.
While I wait for the calls I am starting a new project in which I write books by dead people who never actually wrote any books but would have had a damn good yarn to tell if they had. Watch for my coming novel FATAL ATTRACTION by Mata Hari.