Worth putting a number on the "common good" framing. Two separate buckets are already exposed before anyone touches their wallet.
First, P2PK outputs. Those were the only output type until Oct 2010, and they never hashed the pubkey in the first place. Roughly 1.7M BTC sits in P2PK, mostly early-miner coins that never moved. No address reuse required.
Second, spent P2PKH. Every time a P2PKH address gets reused, the pubkey lands on chain in the spend. Deloitte's 2020 pass at the UTXO set put total quantum-exposed supply around 25 percent once you add reused P2PKH on top of P2PK.
So the purple trapezoid is not a choice we make near Q-Day. A quarter of supply is already in it. The real P2MR vs BIP 360 question is whether we can migrate enough of the blue triangle fast enough that the trapezoid does not set spot.
Worth putting a number on the "common good" framing. Two separate buckets are already exposed before anyone touches their wallet.
First, P2PK outputs. Those were the only output type until Oct 2010, and they never hashed the pubkey in the first place. Roughly 1.7M BTC sits in P2PK, mostly early-miner coins that never moved. No address reuse required.
Second, spent P2PKH. Every time a P2PKH address gets reused, the pubkey lands on chain in the spend. Deloitte's 2020 pass at the UTXO set put total quantum-exposed supply around 25 percent once you add reused P2PKH on top of P2PK.
So the purple trapezoid is not a choice we make near Q-Day. A quarter of supply is already in it. The real P2MR vs BIP 360 question is whether we can migrate enough of the blue triangle fast enough that the trapezoid does not set spot.