the people who pirate it probably weren't going to buy it anyway
Exactly. For example, you can't expect some middle class kid in some third world country to buy the game they like. Playing games by pirating might make them play their favourite game until they eventually grow to a point where they earn themselves and then they buy the games they like.
P.s) Pirated games all this time but the first game I will actually buy will be Spiderman 2. Really excited to try it out since Spiderman 1 was so fucking good.