If you release an expansion on a regular schedule it is just like a subscription. Lets say 200,000 copies of Age of Shadows sold and EA net $10 for every copy, that is 2 million. World of Warcraft has 11.5 million subscribers. If even 5 million bought Wrath of the Lich King and Blizzard made $30 per box (it retailed for $50 I think), then they made 150 million dollars.
Expansion and initial sales are important in their own way. For instance you don't have a subscription until you get the initial sale.
I also read on BrokenToys that Dark Age of Camelot was running in the red at some point. Who knows if that is currently the case. After a few months you can no longer rely on those statements to determine how a game is doing. I don't even remember how long ago the wildly profitable comment was made. According to that article date it was over a year ago.