My manager has my personal email address (I have hers). She has used it once: on the final day of a holiday last year she emailed to tell me that the office was shut to non-essential staff due to a problem with the water supply. That's the way it should be! She also has my mobile phone number, but she's never called it.

When and where are you hiring? ;-)

For the same reason that European rules would plant potatoes in a "guarded garden for the king" so neighbors would want them too: ;-)
There's no better way than artificial scarcity to ensure accelerated adoption.

Plus, replacing the Home screen and interacting with the system at a lower level than probably e.g. Apple on iOS would allow, given the wide variety of Android versions (and hacks) out there that might be incompatible in unforeseen ways, Zuck probably does not want his company to go down in history as the one that (at least temporarily for Joe Avg. Users) inadvertently bricked a hundred million phones or so.

when he manages to remove every trace of phone-home crap in there, then it's maybe news worth mentioning

Then how would it work?

As a "leech-only client to Facebook" for the few who do actually care about their own privacy, but are nosy enough to want to read up on everybody else's every move (from the phones of all those to whom it couldn't matter less as they use an unpatched very verbose version).

...would rather have it as an exposé (pour les initiés) after meaningful peer review. ;-)