Cheap editions and the end of perpetual copyright in 1774
I am a writer, but I'm also a socialist and as such a great advocate of universal education to as high a level and in whatever form possible. Perpetual copyright, while ensuring that you and your descendants retain control of your work in perpetuity (and of course continue to rake in the royalties), precludes the kind of cheap editions that allow someone on low pay to read freely and, by extension, educate themselves outside of school. In 1774 when perpetual copyright ended in Britain there wasn't a network of free lending libraries in every town (of course, that's ceasing to be the case now, but that's another story) and for a worker to read a book, they or one of their circle had to have bought it. The cheap editions of older works that were suddenly possible due to the change in copyright law allowed that to happen.
When I was in my teens, the Wordsworth Classics range was launched: a pound for works of Dickens, Tolstoy, and a host of other, mainly 19th century, authors. At the time I'm sure I could have borrowed any of them from the library but for less than the cost of a return bus fare into town I could have my own copy to keep coming back to. Most of them still grace my shelves. The paper may have been thin and the spines plain grey but the words inside were the same as if I'd inherited a copy with a tooled leather binding. Back in the late eighteenth or early nineteenth centuries that revolutionary cheapening of old books would, if any formally educated man was willing to engage, have enabled me to debate those contents with my supposed betters. It would have let me creep into the citadel of learning.