People pirate because they can and because when factoring in the punishment and the chance of getting caught they come out ahead by pirating.<p>Let's say that a piece of software has price p and that you get value v from it.<p>If v &#62; p, then you will choose to buy it, getting v - p in consumer surplus. If v &#60; p, then you choose not to buy it.<p>Now let's say that you can pirate the software as well, with chance of getting caught c and punishment if caught d. Pirating the software costs 0. If p &#62; c * d then it's economically rational to pirate it, getting overall value v - c * d.