File-sharing and libraries, related?

Matthew Yglesias reminds us that although copyright owners may have been deprived of some economic benefit in the process of file sharing, it isn't dissimilar to borrowing a library book.

Now as it happens, the powers that be have decided that it’s socially beneficial to allow friends to borrow each others’ books even though this results in losses of royalties. The government even funds, at taxpayer expense, institutions dedicated to helping members of the public obtain books without paying royalties to the author.