Sales are lost to piracy, and it is always beneficial to find ways of turning pirates in to buyers, be it DRM or some kind of added value. I'd prefer it be the latter, but that's a much longer, harder, and more expensive route, as it requires added development.
Really, the only thing this affects (in terms of the entrenched game industry) is the PC. Piracy on consoles is low enough as to be nearly insignificant, due to the hoops required to pirate on console, coupled with the potential downsides.
I wish for a magic non-intrusive drm for PC so we could use it as a primary platform again. Sure, shoddy ports aren't helping, but at the end of the day, even non-ports have serious issues if they don't ship with a major online component.
I am completely anti-drm on most medias, but with games, there's a catch: They have no other means of income. When a TV show is pirated, well, they still get money from TV ads and dvd sales. When a movie is pirated, they still have the box office sales. When a cd is pirated, the artist still makes money at concerts.
When a game gets pirated, well, too bad so sad I guess. It's a difficult situation for everyone.