Rubbish. I would argue that it's mostly about pricing.
Look at the AppStore - after jailbreaking, it's possible to crack any app straight from your device and upload it to a second appstore full of cracked apps. That hasn't hurt the AppStore.
But you notice something about apps that isn't the same with music, films or books - prices are more flexible, and they are lower (basically always). Better quality apps charge more (and can afford to), there is more competition for sales, and the price is reasonable enough that people will pay for it, even in the face of piracy.
The media industry is full of titans and moguls, who believe their content unbounded in value. They have no incentive to lower prices, and competition is stifled. The worst thing is that they sell you books and films - these really are less valuable than apps. Nobody re-reads the same books forever; the value of a book or film is less every time you read or watch it. Apps don't do that, and yet they cost much less.
The media industry deserves everything it gets IMO. Piracy will always exist for those knowledgeable enough for it to be worthwhile. Luckily, that's a vanishingly small percentage of people. If you get mass piracy (like with, for example, online movie streaming), then you have to realise that it's a competitive force; people don't agree with your products and won't buy them.
There is plenty of evidence of people paying for things they could get for free (even in the media space - iTunes, Netflix, etc). The reason those things took off is that they were just good products - they sold you something for what seemed a pretty fair value, and they beat the pirate sites at things like reliability. Something similar (that is to say, radically different) is needed today for books.