I am not arguing opinions, principles or ethics, I am arguing pure facts. Piracy has no visible negative effects on digitally distributed products, period. To people who deal with digitally distributed products and the whole market, this is about as undeniable as evolution is to biologists, or usefulness of vaccines to doctors. Sure, you'll always find one who says otherwise, but they're all pretty much bought and paid for (like the guy who faked a study to prove that vaccines cause autism).
Noone has ever been able to prove that not being able to pirate something generates sales, and noone has ever been able to prove that piracy reduces sales. And trust me, many have tried.
In extreme cases piracy IS the business model. Why do you think Windows anti-piracy measures are so pathetic? Because that way everyone familiarizes themselves with this system by using it at home, and then when they go to work, their employer has to buy them Windows (except IT/engineering crowd), because it's cheaper and more efficient than retraining your employees. But that is an extreme example which doesn't work in gaming industry.