What Makes A Writer Necessary?

I think of writing as the creation of beauty and the cultivation of craft in language, as self-expression and social communication and political practice, and I also think of it as a form of spiritual sustenance--but what makes a writer necessary? I would have said honesty, intelligence, sensitivity, eloquence and imagination when I was much younger; and I would have added range and mastery of subject matter and philosophical heft a few years ago, but now I am not so sure. Are writers and their work necessary to most people?