Do you genuinelly think a surveillance society would refrain from watching people's Internet use but not refrain from doing so for their phone landlines?!

Because that makes no sense at all, especially considering that in earlier days it was actually easier to record Internet usage (less data and already in digital format) than phone lines, though nowadays data storage, processing power and even speech-to-text engines make eavesdropping on phone lines easier.

In fact even supposedly Democratic nations have been caugh doing mass surveillance of people's Internet use (that's what the Snowden revelations were all about) - because there were no clear laws on that - all the while phone line surveillance does have clear laws, dating from way back, that require a Court Mandate for it to be lawfully done: it was and is legally easier to do mass surveilance on the Internet even in supposedly Rule Of Law Democratic nations that phone line surveillance.