but at the same time, the amount of bitcoins stolen from legacy addresses could have a catastrophic inflationary effect on the market.
since moving one's coins into quantum-resistant addresses is voluntary, millions of coins would likely remain unmoved. those would be stolen and circulated back into the economy.
1. Not all Bitcoin on legacy address is vulnerable, only address where it's public known is at high risk.
2. Quantum Computer can brute-force private key from public key far faster, but not instant. The actual owner can move their Bitcoin to quantum-resistant address with high fees.