You can look up Gabe Newell's quotes on this, but the reason for piracy often has more to do with the fact that the pirate product is better (or more respectful to the user, or less hoops to jump through) than economic reasons.

Especially for people outside of the US, licencing and region locks can make it extremely technically difficult to source and play a genuine piece of media - whereas the pirate one takes 3 clicks.