What happens when we run out of plots for books?

The more simple or broad you make something, the more similarities you'll find. Since people have been writing stuff down, how many stories have gone along the lines of "boy gets girl, boy loses girl, boy gets girl"? The settings and themes of stories go in and out of style. Right now wizards and vampires and pirates are common, but it won't always be that way. How many of Shakespeare's plays took place in Italy? It will always be possible to keep writing things in an original manner. When we run out of things to write about, we'll also run out of new songs to compose and new pictures to paint.