Last minute change in plans is the reason
Prior to the VGAs, we told you about an announcement for Gears of War 3 that was “not what you expect,” and while it was supposed to happen, it didn’t. We now know that according to Cliff Bleszinski a last-minute change in plans caused the announcement to be pulled.
Apparently, the decision was a strategic decision made from on high, said to be in the best interests of the marketing of Gears of War 3 going forward. While that does not explain what they were thinking or why they did it, it is still expected that some revelation will be made in a future announcement; but we have no idea when that might be.