A lack of ownership of digital goods makes it very difficult to build digital libraries with similar benefits and longevity to physical libraries with physical books. For example, first-sale doctrine does not seem to apply to ebooks, and tools for format-shifting DRM-encoded ebooks cannot be distributed legally due to the DMCA.

Some of the largest intrinsic benefits of ebooks, such as ease of duplication and near-instantaneous transmission to an unlimited number of readers over the internet, essentially for free, usually cannot accrue to readers (and arguably to humanity at large), because of copyright law.

And of course copyright term extension and the elimination of renewal requirements have ensured that many books that would otherwise have entered the public domain have not, even though this copyright extension may not provide much of an incentive for most authors from 1929 to write more books.