A quick thought on cinema, and adaptation of books. Reading one or two reviews of the latest Conan, I was struck by the way so many of us hope movies will be true to the source material.
I'd guess a factor in the degree to which a movie is faithful is the readership of the book and the audience expected for the movie. A movie for general release is a product, maybe primarily a product, maybe even only a product for some.
If it has to sell, it can't upset too many people; minorities call the shots less often of course. So maybe we should read more? But then books are also products - maybe privacy gives a sense of ownership, obscures faults?