Over the years, our family has bought three copies of the Crosby, Stills & Nash
album. My wife and I each bought a vinyl copy back in the '70s. Recently we bought a "clean" (not copy protected) copy from the iTunes music store. I expect that's the last time anyone in our family will have to buy a copy of that album, including all our descendants.
I believe that music sharing is "fair use" within a family. I'm inclined to feel that way about video, and no doubt I'll feel the same way about digitized books. Cousin Jon sent me a couple of links describing "do it yourself" book scanners
. I need to get myself one of those. But a family library of digitized books has an interesting implication for publishers: it will decimate the reprint market. My (not-yet-existing) great grandson won't ever have to purchase a copy of Pride and Prejudice
and should never have to buy any other books I collect in digital form.