We've seen this phenomenon, just on a smaller scale. When an encryption standard is compromised, people either switch to something stronger or face the consequences of essentially leaving their data in the open.

DES was an acceptable standard until the late 90s, but you'd be foolish to use it now. RSA is the accepted standard now, but it is said to fall within 5 years or so. At that point, people will either start paying for a license to use Elliptic curve encryption algos or something new will be found. It's a vicious cycle, but I certainly don't think encryption ends with quantum computing, but maybe disrupts it quite a bit for some time.