I suppose the ideal comprimise would be to allow people to continue ad infinitum based on medical & operational competence, but at 65+ they go back to the bottom of the seniority list or have to reapply for their position. Surely therefore if they are up to the job and love their career so much then there will be no objection. I wouldn't like to think that they want to carry on purely based on the fact they have got to the top of the mountain but want to cling on to the nice view from the top for themselves?