> Why the hell does App A need access to data or notifications from App B.

Advertising networks. Just like how you see crap like a metronome app have a laundry list of permissions that it doesn’t need. Some cases they are just scammy data harvesters, but in other cases it’s the ad networks that are actually demanding those permissions.

Google won’t sandbox properly because it’s against their direct business interest for them to do so. Google’s Android is adware, and that is the fundamental problem.