Nicely put, but what I find most bizarre about the list is that Blizzard jumped from #47 to #1 within the space of a year (you'll find Blizzard's 2008 listing on page 82 of a highly annoying-to-navigate Issuu archive). While part of that's due to the merge with Activision, Develop claims that Wrath of the Lich King being the fastest-selling PC game in history was the greatest contributing factor. Hang on. WoW was doing just fine even before Wrath hit, so how did Blizzard manage to get itself ranked behind do-little studios with sales of around $1-2 million per game on the 2008 list?
The answer lies in how the numbers start getting weird trying to compare MMORPG's to console games. Develop says it "recalibrated" the list for 2009, but I don't know if that means they changed their methodology or simply updated the list doing it the old way -- but I think it's the latter. On the 2008 list they freely admit their approach to ranking game studios based on retail sales is an awkward fit for the MMORPG model, where most "sales" are in fact monthly subscriptions and not the initial cost of the game itself. So that makes Wrath's phenomenal success both a reasonable expectation given the enormous popularity of WoW, and a statistical headache for Develop trying to rank where these studios actually fall in relation to each other.
Does this mean that Blizzard can expect its spot on the list to yo-yo so dramatically from year to year depending on the release (or non-release) of new expansions, completely independent of actual subscriber numbers? That sounds a little odd to me, but we've seen how this issue has popped up before. Lies, damn lies, and MMORPG numbers.