Its reasonable to think things encrypted today with good methodologies are likely to remain secure forever.
NSA can't change the fundamental laws of the universe. While cryptology and mathematics is constantly advancing, there hasn't been a fundamental breakage of a block cipher in ages, nor has any evidence emerged to suggest the fundamentals of RSA will be broken.
Computing power alone isn't enough to break todays strong cryptography, and its certainly possible that the underlying math is a constant of the universe.
Edit: Not to mention the snowden leaks suggests that the NSA spends most of their effort subverting implementations rather than the fundamental mathematics.