This situation seems analogous to when air travel started to take off (pun intended) and existing legal notions of property rights had to be adjusted. IIRC, a farmer sued an airline for trespassing because they were flying over his land. The court ruled against the farmer because to do otherwise would have killed the airline industry.
Microsoft tried to shanghai me to the “new outlook”. When I realized the scope of what they were trying to do, under the guise of a simple software update, I was floored. I don’t even think Google, with all of their Borg-ish tendencies, would attempt such a blatant hijacking of user data. The privacy implications are profound.