To speak to why we need this sort of thing I would have to harken back to a fun talk that Paul Heald gave back in 2012[0] where he showed this fantastic chart[1] that shows the number of titles for sale on amazon by publish year.
The only thing I can assume from the chart is that either the publishing industry in the mid 1900s suddenly found itself publishing the same amount of books as they did in the 1830, no one cares about the books written between 1920 and 1990, or copyright has caused the loss of an enormous amount culture. According to the chart, and the talk, there are 7 times as many books published in the 1910s than are available from 1930s-1950s.
[0]: https://youtu.be/-DpfZcftI00 [1]: https://cdn.theatlantic.com/media/mt/science/Amazon%20pub%20...