In the beginning there was one pilot, and he was called Captain. Accidents happened. And lo the authorities decided to add co-pilots, and they were called F/O. The accident rate was reduced because the F/O helped the Captain to stay safe, probably because the F/O liked to stay alive.
So when ManAdaSystem says
70 years will not happen, of that I'm sure, and a few more over 60 pilots who don't need to listen to reason and then fly with their seniority into a mountain may cause a revised age limit to 60 again.
that would be a major failure by an F/O.......