With Microsoft, their strategy is: Put it for their "User wanted" platform, wait a bit and see how people react, then appease the audience.
It's the reason why they made 7, why they supported XP longer than intended. Every decision was made calculatingly like this. (Like, as many comics stated recently: Subterran Lizardmen).
So as long as people stay off Win 8 for the majority, it'll come to Win7. Last time the update was only a couple months difference.