Re:Why does Amazon have more books from the 1880s than the 1...
by benologist on Wednesday July 31, 2013 @01:24PM
(#6135341)
Sonny Bono also played a part.
http://en.wikipedia.org/wiki/Copyright_Term_Extension_Act
"also known as the Sonny Bono Copyright Term Extension Act, Sonny Bono Act, or as the Mickey Mouse Protection Act"
If it was just Mickey, Disney would survive that somehow, but well, Hollywood started to be relevant in about 1920's, and Mickey was created in 1928, so it coincides very well.