Our parents have something to do with it, but they're not around us all day. Our culture is. In one sense, culture is of the moment, and it evaporates when it is no longer of use. Sociological studies find that human memory, perfect as it is in so many ways, fulls down utterly when called upon to recall the cultural soup in which humans swam even so recently as the last generation. This period seems to be about ten years.
Books exist outside our memories.
They can recall the way things were, and we can recall this information back to us by mean of books. But only if the books exist. Our libraries are full of useless books. We need the space for new books. Or CD-ROMs or tapes or DVD's.