Wingswinger,
In some countries there are no restrictions on age as long as you pass a medical. That means 2 80 or 90 year olds can fly individually or together on air transport ops. Does that make sense to you?
On a recent medical I asked the doctor how he weeds out old pilots. With great difficulty he tells me. He had only failed one on the basis of being 'past it'. He explained that he had no idea how a pilot performed or how he managed to keep the show on the road at 0300hrs on the basis of a 20 min medical. As far as he was concerned the best way was to have an age limit where everyone gave it away.