You may not even know if software you are buying is pirated. A few years back a friend lent me a cd folder full of games. All of them had the game logos on the cds, and most of them had full colour booklets with them. I ended up asking my friend how much he had spent on the games in the folder, and replied: hardly anything, they are all pirated. He bought them somewhere in Asia. They take piracy a bit more seriously over there, you don't just get a blank cd with the games name scribbled on it in felt pen, you get a full colour box, authentic looking cd, the works.
The bigger problem for game companies than people downloading torrents, is illegal factories which are producing pirated versions of games (and other types of software) which can be sold at lost cost, are hard to tell apart from the real deal. Many people who buy these games are unaware that they even have an illegal copy.