Age discrimination will allways exist as long as you use a limit. I explain: whether the limit is 60 or 65 age discrimination is by definition saying that the person who is 60 years is less fit then the one who is 59 and 364 days.
From that point of view the only matter to consider is should there be a limit?
Some people seem to be of the opinion that the only limit is the medical...
P.S. (In Japan I think some people are still fit at 110? In some years we might meet in the cockpit.)