I am wired to care about me, my family, and my friends, and people culturally and physically close to me; that's the way I am, and that's the way you are, too, and so is the first fellow whose lifespan I could be extending, if he were in my position.

I don't think this is true. You are wired at a lower level with all kinds of crazy wires that can tend you or maybe most people towards caring about the things you mention, but these things aren't necessarily the things everyone will end up caring about. Is anyone aware of any relevant neuroscience on this?