Fourth myth: We know that copyright makes us collectively better off.
The evidence points in the opposite direction. Germany had weak copyright laws up until the Copyright Act of 1901. Yet, maybe because of these weak laws, it became a literary and scientific power:
(…), only 1,000 new works appeared annually in England at that time – 10 times fewer than in Germany – and this was not without consequences. Höffner believes it was the chronically weak book market that caused England, the colonial power, to fritter away its head start within the span of a century, while the underdeveloped agrarian state of Germany caught up rapidly, becoming an equally developed industrial nation by 1900. (No Copyright Law The Real Reason for Germany’s Industrial Expansion? by Frank Thadeusz)