'Just encrypt everything' you said.
They will just de-prioritize anything they can't read and spy on with DPI until it's throughput is useless.
It's time to take a look at some serious steganography.
Yes. Categorically symmetric key crypto (the type that is used to secure system drives) is not vulnerable to quantum computer attacks like public key crypto is (the type used in stuff like HTTPS). In the post quantum world, most of the commonly used public-key algorithms will have to be thrown out. The situation is not without hope though. There are many algorithms up to the job.
On the other hand, creating NSA-proof algorithms is a bit trickier. I think this is possible as long as you don't let the NSA on your standards committee and let them dictate curious details like they did with the Dual_EC_DRBG elliptic curve algorithm.