As most of the governments in the world have the technological capability to monitor communications on a large scale they will push to stop messages from being encrypted, demand plain text communications, and/or demand backdoors in the encryption tools.
Current Internet is based on client-server communications where billions of us internet users access millions of web site.
As long as communications go through a server it is easy for some governments to get for ex. a single bucket of all of the emails from Gmail, or all messages on facebook Messenger.
We a the Decentralized web / dWeb project aim to decentralize the way internet is used.
Even is plain text communication will be required by laws decentralized type of communication will prevent large scale surveillance of the population.
As some answers pointed that there is legal framework on getting a court order to get access to communication.
Decentralized type of communication does a technological enforcement of the legal framework.
It makes sure there can be only focused investigations instead of mass surveillance.