If the undermining of intellectual property rights via technologies like the Internet (sounds kinda less scary than 'piracy', doesn't it?) would have a significant negative effect on business (such an undermining should work like a tax or tariff), prices would indeed be higher. But sales would also be lower and it seems to me as if the music and movie industry is doing quite well.
I don't wanna defend anyone who makes a living with intellectual theft, but we have to keep in mind that a) it is impossible to get anyone but the 'big fishes' and b) that the theft of intelelctual property is different than stealing a bread or, an actual topic, part of your 401k. The original still exists and (less so with movies and music but more so with useful information like books, articles etc.) a free flow of information can make people smarter and better informed.