5 million is a huge number, but as Jason said, I can't imagine how many millions of people play pirated games on PC, probably a lot more.

We should thank ourselves to keep the industry running, I don't ever want to see a day where there are no games to play ;p

Steam and iTunes Music Store work on the same principle. People would be willing to not pirate if you make going legit very easy and fairly priced. iTunes with their $1 songs was great. You didn't have to learn a new program every few months. No more questionable quality, great speeds on all songs.

Steam has the same thing going for it. It's insanely easy to use. All your download are in the same place. You can redownload them as many times as you want without worrying about counting computers or activations or anything. Plus the prices are very cheap. Sure Skyrim may be $60-$70 but you can get an insane number of games for <$10 on Steam if you look at a year's catalogue. I myself got L4D and L4D2 for about $4 combined during their L4D Dollar sales.