It's true that you can't have privacy or security in the mass-market apps or in voice or sms over big commercial carriers. However, if a device solved the problems indicated by (username) revelation and following posts on this page, you could then run secure applications - e.g. something with public-key encryption and PFS for the data, and a p2p or tor-style network to obscure the metadata.

It still wouldn't be perfect, but would succeed in many scenarios and would greatly increase adversary costs.