Barriers to entry for printing kept getting higher until the mimeograph, and I think the barrier to entry is more relevant than the overall efficiency per copy. In order to get those efficiencies, you needed a factory, essentially, and factories are easy to find and legislate about. Similarly, Prohibition didn't work because it was so easy to make your own in your own home (or the woods). Other drugs have been somewhat easier to legislate effectively against because they require more infrastructure. Marijuana is the exception, and that's also the most widely used illegal recreational drug. "Coincidence? I think not."