@hazelweakly
The national security thing is I think different. The core goal of the state is to survive, and the primary survival tool of the state is control, so states always want to control everything they can control that could impact their survival. So the driver for universal surveillance isn't that it's going to improve state security, it's that universal surveillance is now possible. If in thirty years we end up with brain implants becoming common, then in forty years we're going to be having a debate about whether freedom of thought is compatible with state security, and the answer of the state, sooner or later, is going to be no.
This calculus means that it doesn't really matter if new surveillance is going to work, let alone be efficient. Just as many companies try to do quantitative security tracking when they don't and likely never will have quantitatively meaningful data, because governance is supposed to be about risk and that means we have to have numbers, so by god numbers we will have, the state does the same. Better yet, the state gets to never actually tell you what the numbers are. "Critical for national security" is a magical formula, not an analytic outcome.