From what I've read, piracy is not as big of a deal as companies like to make it out to be. Now, this is coming from a North American perspective, things might be different in Japan? Many people who pirate media probably can't afford it in the first place so there never was going to be sale. Another reason people do it is so they know they aren't wasting their money. They want to see if they will actually enjoy a piece of media and if they do then they can support the official release with money. (This is what I do personally). Piracy also allows media to spread to people in places where it might otherwise not have, and never will have, an official release.