Arbitrary retirement ages have usually been campaigned for and enforced by those who find their own careers threatened by the "old age and treachery" crowd.
But with more and more of us living into our 90's and beyond, demographics becomes the issue. It's really a case of fewer and fewer worker bees supporting more and more healthy retirees. My father died at 93 with seven decades of entries (1930-2000) in his log books.
There is no longer a reason for an arbitrary retirement age - and CERTAINLY not for pilots at age sixty.