Think about the most notorious authoritarian regimes. Third Reich, GDR , USSR, Mao's China. They had relatively weak surveillance capacity. Secret police had to personally spy on the target and manually install bugs/taps. Technology was primitive and error prone. Most casual conversations were less vulnerable to spying. Rural people were relatively safe. Private conversations could be easily held in secret (e.g. walk…
Yes, though on the flip side, that power is very fragile now, relying on complex, difficult to maintain technology, with high overhead costs (aggregate, not individual). They can also more easily be turned against their creators or those who believe they have firm control but don't.
That power is actually less fragile than ever, given there are for-profit entities ensuring their continued existence. The State doesn't need to deploy mass surveillance tools when they're built and maintained by private industry. Regular payments and court orders ensure the State has ready access to any of the data they might want.