No, piracy doesn't remove the possibility of rewards for your work. In many cases the people that download, for example an MP3, would not otherwise pay for that work. In a lot of cases they wouldn't have even known about the artist/work in the first place.
I used to download music, but now usually listen to music on YouTube, or some other streaming service, since that is easier than downloading music in a lot of cases. A lot of the times I would just go to Napster or something like that and just search for, and download, maybe 100 or so songs at a time just by searching for 'remix' or something general.
Sure in many cases it would be a song by an artist I have already heard of, but a lot of those songs would be by people I have never heard of, and a lot of those artists were very good. It wouldn't be fair for anyone to say my download took anything away from them, because up until I downloaded that song they were unknown to me. But now I probably visit their website, facebook page, YouTube videos, or follow them on Twitter. So while they didn't lose anything from my download, they did gain something.... Another fan.