To make this more precise think about what you would do if you had to choose between Life Extension and Replacement for a group of people, none of whom yet exist. I think the intuition in favour of Life Extension is the same, but I am not sure (I also find it very likely that I am actually indifferent ceteris paribus, for some value of ‘actually’ and sufficiently large values of ‘paribus’).
To make this more precise think about what you would do if you had to choose between Life Extension and Replacement for a group of people, none of whom yet exist. I think the intuition in favour of Life Extension is the same, but I am not sure (I also find it very likely that I am actually indifferent ceteris paribus, for some value of ‘actually’ and sufficiently large values of ‘paribus’).