[ReidZB]

Here's food for thought: What would be required to make a nontrivial fraction of TLS traffic on the web post-quantum secure? How much would it cost?

What about other legacy systems?

Actual, physical quantum computing is still in its infancy, so sure, it's hard to conjure up the wherewithal to worry. But nonetheless we have a long way to go before we can say the world is ready for real quantum attacks.