I wrote this comment in relation to a blog post by Kate Carruthers. I was remembering a speech I heard on a great speaches podcast about how the printing press had brought mass publication into the realm of many more people and how there had been many many publications 100 years ago. But then the rise of the big printing houses and their hight tech presses reduced the variety. But now I think the internet is changing the economics the other way.
I agree with what you have said. But computers have added a new issue. With a book you can sell or lend it out. But photocopying it was not available until recently and then it is a long and relatively expensive task to make a duplicate copy of a book using a photo copier. With a computer file, making a copy is in fact the default behavior. So now not only are books or other works portable as happened with the printing revolution, but making copies is now extremely easy and can be done at basically no cost.