I think everyone needs to breathe and remember Apple has not said they won't debut the new AppleTV, some undisclosed random source has said that.
While normally nothing is for sure, Apple added the AppleTV into the actual invite, yes the center of the invite has the exact shape and proportions of an AppleTV. So we will see AppleTV at the event. However, what this means probably is that as previously rumors have said, they haven't finalized the necessary deals with the TV networks for the TV streaming service. So the new AppleTV at the moment might not be as exciting as it would have been otherwise. So this may have been a controlled leak by Apple, so people will go from expecting a lot of the AppleTV, to not expecting one at all, and then be happy when one is announced (albeit let than what was originally anticipated.