That's because, despite the fact that the events in New Avengers have been unfolding over the course of a few weeks (months?), the Illuminati haven't deemed anybody else in the Marvel Universe worthy enough to know about their little secret.
From how it sounds in New Avengers, it's been more like weeks. Not much over a month.
You keep acting like the Illuminati are going to come out of this smelling like a rose, which will im most all probability won't happen. Stark's gonna pay for mindwiping Cap, Black Panther and Namor are gonna end up in a death match by the end, it sounds like Dr. Strange is gonna pay a big price for using his magiks in this mess. Black Bolt will most probably lose his throne over this, and someone is gonna end up banging Black Swan (which won't end well).