It is said that when Truman Capote died Gore Vidal commented, “Good career move.”
Maybe that is a bit crassly stated, but frequently the death of an author will result in a tremendous upsurge in book sales. Not only that, but sometimes posthumous works multiply. Consider the list of posthumous books by Ernest Hemingway (source: Casanova Was A Book Lover);
A Moveable Feast (1964)
The Fifth Column and Four Unpublished Stories of the Spanish Civil War (1969)
Island in the Stream (1970)
The Nick Adams Stories (1972)
Along With Youth: Hemingway, the Early Years (1985)
The Dangerous Summer (1985)
Ernest Hemingway: Dateline Toronto (1985)
The Garden of Eden ( 1986)
The Complete Short Stories of Ernest Hemingway: The Finca Vigia Edition (1987)
Hemingway: The Toronto Years (1994)
The Good Lion (1998)
At the Hemingways: with Fifty Years of Correspondence between Ernest and Marcelline Hemingway (1999)
True at First Light (1999)
[A few of the above are either biographies or collections that contain previously unpublished materials.]
Wow, Ernest Hemingway published more after he was dead than most of us will during our lifetime.