There's a fundamental difference to both the pre-phone and the pre-Internet age: In the grand scheme of things phone tapping is a relatively new affair. Before

There's a fundamental difference to both the pre-phone and the pre-Internet age: In the grand scheme of things phone tapping is a relatively new affair. Before the general availability of phones you needed actual human snitches to spy on dissidents and deviants. Even once phones were widely used oppressive regimes still needed a huge number of human agents because not every conversation happened on phone. Physically spying on others is both dangerous and expensive, which is why it's usually done selectively. All of that changed with the general widespread use of digital means of communication: Not only do most dissident, potentially 'dangerous' conversations take place in digital media but those conversations are also easily available for governments to harvest and draw upon to whatever end.