The first person you should think of pleasing, in writing a book, is yourself. If you can amuse yourself for the length of time it takes to write a book, the publisher and the readers can and will come later.
Each book is, in a sense, an argument with myself, and I would write it, whether it is ever published or not.
I can't write if someone else is in the house, not even the cleaning woman.
If people have bought something of mine, they know by now that I will decline writing it for the movies