Ultimately, piracy breaks down to "people want your stuff, but you've priced it too highly". In the case of apps, that's all it is. In the case of music, it's a little different. Music is cheap, but it's rare that you can get it in a good format: everything is lossy, and for people with good audio kit and good hearing, that makes the music unusable. Therefore, people that both Want It Now and want full quality are going to download the FLAC torrent rather than buy lossy MP3s. (They won't buy the CD because it takes too long for the mailman to deliver it.)
The same goes for movies and TV. Nobody will sell you those things without DRM, so if you use Linux exclusively, you have no option but to pirate the content. Make every TV show a standard non-DRM'd HTTP download for a buck, and piracy (among people with money) evaporates instantly. But the content producers want a bogeyman to blame for all their problems, so they intentionally keep piracy alive.
(If there were no such thing as the ability to pirate movies, people still wouldn't have bought the 88th redo of Star Wars. We liked it the first time. But it's easier for Lucas to blame the evil greedy pirates than his evil greedy self.)