Often it is more than just language.

When a Civilization rises up and flourishes, the literature goes through development. It must be great for Authors to be able to be the 'first' to strike upon certain themes. The same for Music and the Graphic Arts.

But in an old Civilization, then everything really has been done. What can anybody do?

Look at our own Literary Civilization. Authors have grown so frustrated that they invented Sci Fi -- total Bullshit where they just make up new worlds and manners so that they can have something original only by creating things that are entirely meaningless.

Indeed, if Civilization should ever fall, then somebody should be appointed who will discretely burn the Libraries. No, not everything. but certainly enough so that the Intellectual and the artists of the Next Civilization will have the fun of Re-creating what had gone before without having to feel hopelessly derivative.