When I was younger I was a very good driver (shades of Rainman) but as I've gotten older my driving skills, particularly my vision, has declined. This is normal and it's what I thought of when I read about the extension of the retirement age limit for pilots.

But flying an airliner these days is less like driving than it is like managing. Training and experience play a more important role than coordination and reaction time. So let them fly until they're eighty.