I am a professional translator and earn my bread through books, and yet I don't make a very high idea of literature. I don't think it is more important than, say, culinary or swimming. Of course, literature (and written texts in general) can give us such views of history and of society as are unatainable by any other vehicle. But most people can fare well without a wide view of history or society, and even though literature is my favorite subject, I believe people in general would prefer a pizza to Shakespeare. I would suggest them to have both; but if they must choose one, let them choose the pizza.
I don't mean by this that literature is worthless. But it requires a capable reader. Who is this capable reader? Sure, it is the professional student, who works with literature to solve questions of history or sociology. But it is also, as Navaid said, anyone who is able to get amusement or instruction from a text. Whenever a reader can put a book aside for a moment and say "Hey, it's good to read this stuff"; whenever he can better understand his world and times, or deal with people, or simply tell a joke - then literature is justified. I doesn't please everybody: true, but a pizza doesn't eithe