my simple answer is, encryption works by creating a function which is vastly more costly in one direction (encryption) than the other (cracking).
for any computing power available, if you apply x seconds of computation to encrypt with a complex key, it will take a multiple of x years to crack it.
as long as that multiple remains, which cryptology seeks to improve, just applying more computing power will never obsolete modern encryption methods.
It is worth noting that modern cryptography generally considers a system securing only if it takes exponentially longer to crack than it does to encrypt. That is to say, the cryptosystem defines some security parameter y, and legitimate operations can be done in O(y) time, while attacks require O(b^y) for some b>1.
Even quatom computers require superlinear time run Shor's algorithm.
for any computing power available, if you apply x seconds of computation to encrypt with a complex key, it will take a multiple of x years to crack it.
as long as that multiple remains, which cryptology seeks to improve, just applying more computing power will never obsolete modern encryption methods.