Copyright does not expire for a very long time. Harry Potter and the Sorcerer's Stone was released ~30 years ago in 1997. It remains protected for the duration of the life of the author (J.K. Rowling) plus 70 years.
Given actuarial tables from the UK[1], this works out to be around ~95 years from now (~2120).
[1] https://www.ons.gov.uk/peoplepopulationandcommunity/birthsde...
The library of congress does distribute some digitized works that are out of copyright. And it does digitize some works for archival and distribution, but having additional works digitized for (eventual) public use could be nice.
It is not at all clear that this is true.
The number of books published every year is growing rapidly. According to Bowker the number of books published in the US every year has increased ~15x in the past two decades [1].
Because of this, I suspect that the median age of the books we are discussing is below 30 years.
[1] https://www.writercosmos.com/blog/how-many-books-published-p...