NIST's draft transition roadmap would deprecate elliptic-curve signatures after 2030 and disallow them after 2035. Bitcoin, Ethereum and Solana all sign with elliptic curves. Replacing a signature scheme is not a patch. Spending from a Bitcoin address publishes its public key, so every address that has ever sent a transaction is already exposed, as are the 2009 coins paid to public keys directly. Protecting those requires someone to still hold the keys and actively move the funds. Nobody moves the lost ones. The rest has to happen in one window: every exchange, custodian, wallet, miner and bridge on new keys at once. Anything left behind becomes a target the day the old scheme falls. For scale, SegWit took two years and nearly split the network, and it never touched what makes a signature secure.