> the Stasi already had the capacity for that 40 years ago.
I disagree. I haven't lived under Stasi but I have lived through Martial Law in Poland in 80s.
Yes, when you have picked up a phone receiver you have been greeted with pre-recorded message that "your call could be recorded", there were tanks on the streets and secret police everywhere.
But more or less you realized that state capacity is quite limited - political police could not practically analyze every recorded phone call of every single citizen. Police could have messed with life or even kill some dissidents and beat or shoot at people during street protests but they were not able to identify every single participant thereafter. In mass of protesters you were safe.
Also you could just leave the system, go into the mountains, find some job and live simple life without being bothered by the state.
This is not an option nowadays. Even democratic state has an abbility to trace every movement of every citizen. You could be traced and fined for every minor offence like traffic, your conversations, your movements are constantly recorded. You are tracked not just by the state but also by private surveilance economy.
And most important it is much harder to just leave a system. Your biometric ID, your banking apps, your credit score, your vaccination proof, your health records, your smartphone will follow you to the most remote in the country.