If you go to China, they know what every citizen buys in real time or near real time. They have the digital infrastructure to do this. They don’t have the computing power to do it as fast or detailed as they like. Presumably AI will provide the digital infrastructure.
Presumably, this will include knowledge as to what you buy from your neighbour with digital cash. The only way to avoid this will be bartering, but the government will have the record as to who originally bought what you traded for and they can quickly work towards tracing that item to you.
AI is going to change a lot. Too bad congress will wait until it’s too late to do anything as always.