Development teams vary quite drastically in size across platforms ...
If you're developing a high end PC game, or HD console game, it isn't that unusual to see development teams that are more than 100 people; in contrast a lot of Wii games (in particular a lot of Wii games that third party developers are working on) can have development teams in the 20 to 40 person range. If you look at a Nintendo DS, Wii Ware, PSN or XBox Live Arcade there development teams can actually be under 10 people.
On top of this "video game professionals" who read (or subscribe to) Gamasutra or Game developer magazine and respond to a voluntary survey may not be all that representative of development studios as a whole. I used to read Gamasutra quite regularly, and (from what I saw) its articles tended to be far more useful for an engine programmer who is working on a cutting edge project than anyone else in the industry; if you're working on very conventional technology (PS2, Wii, PSP or Nintendo DS) the value of reading Gamasutra, and I assume Game Developer Magazine, is probably not that great.