That's a backwards way to look at it. Copyright is a very powerful protection, we sacrifice a lot for it (look at all the creativity that's still going on around Sherlock Holmes, or in illegal fanfiction for more recent works, and think how much more creative expression there might be if more cultural icons were without copyright). The bar to justify extending copyright to something new should be set high; I'd rather risk having fewer old books scanned than have someone unable to make a new creative work because he'd got the idea from a scan of an old book that turned out to be copyrighted.