Other commenters have mentioned about how pirating can increase exposure and in fact increase sales - Breaking Bad (which isn't music) is one big name example of this happening.

In any case, "album sales" is a very one dimensional view of the world. Even if fans were to pirate music, there is no way to pirate live performances - and exposure is one such way to boost sales of live performances so lost sales in albums is a very narrow slice of the entire ecosystem.