I guess that my own response to the repugnant conclusion tends to be along the lines that mere duplication does not add value, and the more people there are, the closer the inevitable redundancy will bring you to essentially adding duplicates of people you already have. At least as things are at present, giving an existing person an extra hundred years seems like it will involve less redundancy than adding yet another person with a hundred year lifespan to the many we already have and are constantly adding.