... almost all the time [one is on the digital grid]

The more capability superpowers build into digital tracking, the easier it is to leave that behind.

If I took a bag of cash, left all digital devices and credit / banking cards on my table, and walked out of my house, I find it incredibly hard to believe the US government could reliably track me if I wasn't already marked for surveillance.

China, I might pop up on a camera, but there are ways around that.

So yes, agreed if people are connected and behaving "normally." (I.e. buying things, showing their id, etc)