Earlier quoted context omitted.
Airline pilots have a legally mandated retirement age of 65. Running the country seems like it's at least as mission-critical as flying a plane.
That's a completely different situation. It's measurable biological certainty that reaction times as measured in milliseconds and fine motor control degrade with age. Vision and hearing also degrade. The nature of hands on control of flying a plane means there are no ways to compensate for this. None of this applies to a politician making decision in a time span of hours, days or months and who can delegate tasks as…
But I think the argument is still valid for other reasons.