The following, though, does remain the law of the land:
The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.
https://en.wikipedia.org/wiki/Kyllo_v._United_States
I think the future of this doctrine is unclear.
But that's what parallel construction is for, I guess...
A group of people with a warrant gathering detailed routines of a suspect is one thing.
An apparatus that can observe the detailed activities and whereabouts (location AND behavior) of all people in a metro area is a completely different thing, and one our courts and Constitution have not yet handled.
My original point was I find the "It's too efficient" argument to be a very weak attack angle on the use of technology in surveillance.
Exactly. It's one thing to say our laws and Constitution should place strict limitations on this kind of surveillance. I agree with that.
But it's another thing to say they already do, when they don't.