As noted above, if the pirated software does not represent a lost sale but is used for something that is a net benefit to the economy, it's a positive effect. And even if it does represent a lost sale, it still might be positive if revenue is redirected from the movie industry and instead to something that has a higher multiplier value like some more labor-intensive thing.
Clearly the assumption that it's all loss is ludicrous, the people who pirate software or whatever probably are mostly in segment of society that already use all their disposable income. If they couldn't pirate, they would either forego it or redirect their spending from something else. Given that the net savings rate of the US population, at least, is negative, it's not like people are hoarding cash while pirating stuff...
Assuming that each download is a spoiled sale is utterly wrong.
People download stuff from net because it cost them nothing, they have good connectivity and the process runs in background. People share stuff because it cost them nothing.
Sharing works only on flat-rate tariffs. That is the starting point.
That point always bothered me about the whole "our economy loses X billions because of piracy". If people would have purchased everything they pirated, then some industries would have gained those X billions, but the flipside to that is that other industries would lose the same amount of money. So you would create Y million jobs in the entertainment industry, but you'd lose Y million jobs in other industries. Is that an acceptable trade? Probably not.
When someone pirates something he may otherwise have paid for, it isn't necessarily a net loss in production. Imagine that one person pirates software A, which he would have bought and spends the money on software B, which he would not have bought. Now imagine another person does the reverse.
Same amount of money goes into these two software companies, twice as "much" software comes out. There is a consumption benefit (that goes to the pirates). If the pirates use that software to create more wealth, that is benefit leaking back out into the rest of the economy.
Because of the way size is usually calculated (like volunteer work), we wouldn't count that pirate as having gained anything. That is probably not the right way of looking at things. Even if it is, it is very hard to say that anything "cost the economy X.'
