Most systems are designed around success. Ethereum's quantum migration plan also spells out what happens if it doesn't work.

Buried inside it is a provision most people don't know about: the Minimum Viable Post-Quantum Protection. It isn't the goal - it's the fallback if the plan itself stalls: five hard forks, running in parallel, against a deadline set a year ahead of the expected threat.

A fallback plan, already assembled, for a failure that hasn't happened yet.

Companies typically write postmortems after something breaks. Here, the postmortem came first - before the threat even exists.

There's still no quantum computer capable of breaking modern cryptography. But once one exists, the clock effectively runs backward: a transaction signed in 2019 becomes vulnerable retroactively, its signature crackable by whoever gets there first.

Ethereum has given itself until 2029. The threat is expected around 2030. That year of slack is deliberate - less caution than a specific bet about how fast things can go wrong.

Building a fallback for the fallback, on infrastructure holding roughly $300 billion, reads either as paranoia or as one of the more serious pieces of engineering out there. I'd call it the latter.