End to end, but to which ends? I seriously doubt that MS will cut itself off. There are too many reasons (national security response, marketing, police investigations etc) for them to keep at least some access to content in extremis. The "end" will be some midpoint within MS systems or control.
Also empty words are one thing and deeds are another. We can look at MS past actions which already happened, and one of them was - the first thing they did after buying Skype was to disable p2p calls which they couldn't intercept, and reworked app architecture to centralized.
