The larger problem is that there is information asymmetry between the weak and the powerful. The powerful know almost everything about the weak, and it becomes

The larger problem is that there is information asymmetry between the weak and the powerful. The powerful know almost everything about the weak, and it becomes trivial to discredit any of them based on some past evidence they can dig up. The weak know nothing about the powerful because everything is top secret and they use the former tactic to deal with anyone who speaks out. The goal isn't necessarily to collect everything. It is just to convince the population that they're being constantly monitored. The fear that they'll be "silenced" for speaking in public about the wrongdoings of the powerful is enough for most people to submit to their demands. Anyone who claims they "have nothing to hide," is delusional. Once enough people are in that state of fear, the state can make up something you done wrong and nobody is going to risk their neck to try and defend you.