There is a detail that makes it possible: the absurd over sharing everywhere. If only everyone did not think to plaster everywhere their face with their selfies and decide to share everything everywhere, then maybe something like this would be a lot harder to implement (if possible on certain cases)
This is also a good perspective. One thing I was thinking just now: at some point, side loading on iOS will be a thing. I wonder at that time we can truly use an iPhone without an account at all (not even to install stuff), but my guess is, considering their track record, they will do the wildest malicious compliance possible…