I dont wanna flame anybody here, but u guys should know, especially the guys who have consoles, and of course u have PCs too and probably play on them a lot too.
But my thought is that sales are so much bigger, because consoles appeal to the more casual gamer, the person who picks it up 1 nite, plays a bit then leaves it for a month then comes back and so on.
While PC games have a more hardcore community, because usually u invest a lot more into ur PC giving u the motivation to play more on it.
This also leads to gamers being a HELLUVA lot more pickier on PC than on Console, as i stated above, the casual gamer will play anything that takes his fancy as he wont read reviews or get advice and stuff. He or she will pick up and play pretty much anything. But the PC gamer will give more thought into these games and will be generally more critical about them.
Which also leads to why there have been so many games missed but have been spectacular... "cough cough" Freespace 1 and 2.... It was and still is in my books the best space sim EVER. Except for freelancer, but that was more of an rpg really. But no one really bought it, which i found really strange.