And these are precisely the people who won't be watching the reveal of a new console.
If Microsoft gave a 'core gamer only' conference as its reveal, the (e.g.) CNN article the next day would read very differently. And the mother with two children and a kinect would decide, in a paragraph or maybe two, that this next one is not really 'for' her.
And that may well be what core gamers want the message to be. But it is desperately not what Microsoft wants the message to be.