At least in my opinion, the ultimate goal of Free Software is to kill copyright. In a perfect world, everything would be public domain and at the utmost, we'd have a right to attribution (ie, you may demand to be named as the creator of something you made). Copyleft is, right now, just a "necessary evil" to bring us closer to that goal. In a sense, it's a form of using the enemies' weapons against them - but what we actually want is mutual decommissioning.