I wonder also, about the copyright limitations. Classical music excluded, such longevity was not possible before. My vinyl LPs are all scratchy. But I can play the CD copy now, even if it doesn't sound as full. Up to now, items like radio, TV, even stereophonic turntables, have been housed in the home and hearts of man, due to their length of existence on the Earth thus far.
Books are the reigning masters of longevity.
We have a couple of generations or more of associated memory. Almost a species memory now for books. Some of my friend's children have never even had an audio cassette player. I have a sneaking hunch some things will fall through the cracks because of this. So all of this contributes to the entry point.