Surveillance and technological "neutrality"
A big assumption lies in choosing the technological baseline of surveillance. Usually this is, conveniently for governments, chosen to correspond to some high-water mark of surveillance, for example the copper era when phone exchanges were centralized and wiretaps required only splicing together copper cables.
The most accurate baseline, however, is the baseline abilities of surveillance that our laws, especially our Constitutional laws, were designed for. In the United States, the Fourth Amendment was designed for a world in which governments had no ability to wiretap. If a government wanted to spy on your conversation they had to do it the same way they can still do now -- by following you around and listening in person (or at least in the next room). On very rare occasions, you might write a letter and the government might open your mail, for which "paper" the Fourth Amendment required a search warrant based on swearing under oath that there was probable cause to suspect a crime related to that mail.
In short, the "technological neutrality" argument, if applied correctly, leads to the opposite conclusion reached by its proponents. Rather than reacting to privacy technologies by reducing further our legal rights, instead we should be expanding our legal privacy rights and encouraging privacy technologies until we return to the baseline of government surveillance abilities for which the Fourth Amendment and similar protections were designed.