Isn't the very nature of Office Open XML Format is to allow support for different versions of Office apps to with different feature sets to work on the same file without rendering it useless? It certainly isn't free to implement but it isn't near the scope of adding VBA support to the web and WP versions.
It means that since there's an opportunity cost to every feature, and an actual cost in terms of testing and implementing it, your feature can't merely be "better than now" to be implemented. Every line of code you add has to be maintained, localized, tested, potentially adds a security bug or a feature that you have to backwards support, so features have a high opportunity cost.
You seem to consistently mistake my attitude as being one of saying "MS don't need to add that feature" as some kind of "defending" Microsoft. It's actually quite the opposite. I'm saying that they should be implementing better features, because if you only get to pick say 6 new features over the next few months, I'd rather they be ones that people want, rather than ones like VBA on a WP that so far as I can tell, few if anybody actually need.