This is a real concern and it's good to see it being discussed seriously.

The problem is clear: current Bitcoin signatures (like Schnorr) are only 64 bytes. Post-quantum signatures are several kilobytes. That means fewer transactions per block and higher fees. Any solution has to be both quantum-resistant and compact.

SHRINCS having a concrete BIP proposal is a big deal. Even if it's not for production use yet, having a reference implementation means the conversation is moving from theory to practice.

Do you think the Bitcoin community will adopt a post-quantum solution before a quantum computer becomes a real threat, or will it be a race?