Why would spy agencies wanted to read people's messages from server, when they can get plain text in each device ? Nonsense. Current encryption type secures only storage and transmission states. What secures kernel, decryption, caching and read states ?
Attacking all end devices all the time is incredibly difficult. It simply not economically practical.
So we need to secure all communication and all data at rest. That's most important. Fixing all bugs in all end user devices is a hole bigger problem (or doing something to avoid escalation). It is getting a lot of attention too, for example Linux Kernal Hardning project). People switching languages away from C also helps.
