I agree with the argument that it is less about sudden incapacitation and more about a slow degradation of skills and ability to stay awake for 16+ hours back of the clock. I routinely fly with First Officers who are 65+, and one who is 72. I am 32, with 8000+ hours and am still a Second Officer. My main gripe though is not about slow career progression, I knew this would be the case when I joined a "legacy" carrier. My chief complaint is that we are required to carry these guys, both in the Sim, and on the line. With very few exceptions, in my experience, once they are over around 60 or so pilot performance drops off markedly. What this leads to is a degree of animosity in the flight deck. I know it's bad for CRM but if I see anyone taking "uncontrolled" ie unbriefed, sleep, I now report it. In the sim, I only help as much as I am required. SOP's and no more. I don't socialise with over 65's on layovers. A large reason why many older guys carry on is the social side of the job. It's a bit harsh I know, but I call on all those who don't agree with over 65 pilots to do the same.