You're missing the point of copyright: copyright introduces artificial scarcity in order to increase the value of books. That is why you can lend/borrow books, resell a book, etc.. In that respect, it isn't all that different from the computer that you write on. That computer is protected by a slew of patents, but you can still lend it out, sell it, aren't expected to pay for it each time you use it, etc..

Copyright is good in that respect because it tries to create a balance between the creator's and consumer's rights. Free "knowledge" is not good is not good in that respect because the focus is on the consumer. Pay-per-read is not good in that respect because the focus is on the creator.

Admittedly there are problems with copyright in the digital age because it is too easy to duplicate information, and we do need to tweak copyright because of that. Alas, the solutions that I have heard don't respect the rights of both parties so copyright remains the best option we have.