This whole debate is a red herring.
The NSA already has backdoors[1][2] in your Desktop OS (Windows, OSX), in your mobile OS (Android, iOS), in your smartphone hardware (Qualcomm Baseband), in your ISPs network hardware (Cisco, Juniper), in your server hardware (Dell), in your network hardware (most router firmwares), and there's rumors they have backdoors in Intel and AMD CPUs, too.
Why would they be concerned about encryption that runs on top of hard- and software that they can control at will?
[1] https://gigaom.com/2013/12/29/nsas-backdoor-catalog-exposed-...