Microsoft gloms together the pay-per-use/subscription part that totally doesn't need "the cloud" (Office apps) along with the other bits that do (email, Skype/Teams, OneDrive, etc.). It makes sense that they do from a financial reporting perspective, because they sell them and you buy them as one thing.

How exactly should they split out the email or OneDrive component from Word or Excel of your $10-20/month? I don't think there's really a sensible way to do it without overcomplicating things.