Apples and Oranges (or Windows, I guess) much?
What exactly does a desktop/laptop OS made by Microsoft have to do with a new iPhone? Pardon me, but I don't see the connection. MS is not exactly competing with an iOS device through a version of traditional Windows. If it was a version of Windows Phone then yes, it would be foolhardy to launch a product in that market segment immediately following new Apple products.
If Apple was unveiling a new OS X version or even new Mac hardware then it might be cause for delaying it, but since full fat Windows has little to nothing to do with an iDevice, I see no reason that the launch of new iDevices would affect the launch of a new Windows version at all.