I was one of NJ's chapter coordinators for 2 years and have been a member for years. I'm friends with people on the board of the IGDA and coordinators throughout the US. The IGDA has, in the past, provided a good way for non-developers to interact with a tiny quantity of professional developers.
I have found, however, that official "get togethers" and knowledge exchanges tend to have significantly more students, indies, and wanna-be's than professional developers. As I run a professional only group, I have to say, none of us want to be constantly asked the same questions over and over again.
What we want is an environment of professionals talking to other professionals. That's really hard to do. Game development is like writing, everyone thinks they can do it/wants to do it.
It might seem exclusionary, but I've started a professional game programming get together in NYC. How do you find out where our location is? Well, a member has to invite you. How do you get invited? You need to know a member. Members currently are senior and above game engineers each with at least four shipped titles. Yeah, that's exclusion; but, we have more fun than we do at IGDA events and talk waaaay more shop.
In conclusion, the IGDA (and even, to a good extent, GDSE) is awesome for indies, students, and whatnot; but, for professionals, we really want a more focused environment.
Hope that helps!