Now imagine you're in 2140, reading that 1980s football player's autobiography: almost every page would contain something you never realized about the past. An etiquette book from 1832, for example, is far more valuable to us now than it was in 1852.
There is certainly value in keeping some copies around for future historians. However not every local library needs to or can afford to, and they aren't of much value to the people who use the library.
That's perfectly correct, and a sensible response. The comment I replied to, however, was simply saying that those books need to die, which is much less sensible.
