> If they can crack encryption they're not going to tell us and they will probably act like they can't.
The thing that was pretty apparent from Snowden's leaks is primarily that they don't need to. This fear that "NSA can crack cryptography" is the wrong fear. First, as others have noted, there are legions of other researchers evaluating and attempting to break widely used crypto-systems. There is no reason to believe the NSA has some unique brilliant minds that aren't available elsewhere.
More importantly, though, why bother with a "frontal assault" on breaking crypto schemes when endpoint security is a million times more hackable. That is, usually at some point someone wants to view the encrypted data that is being sent, and at that point it needs to be decrypted, so why not just try to hack at that point (which is exactly what they do). As an example, just look at all the stolen cryptocurrency heists. All of these heists resulted from stolen keys or from implementation bugs, not from cracking the crypto schemes that protect cryptocurrency in the first place.