We already have a sperm/egg donation industry. Why not pay people to be blood donors? I'd probably participate, although the only blood I've donated so far was just a couple of small vials for a study. Aging members of society would get younger blood, which young people such as myself already have plenty of. I get money, which (if I'm still in college by the time people want blood transfusions) they have a greater capacity to earn than I do. Everyone seems to win.
Why not save it for yourself when you get older? For that matter, why don't you store your own blood now for yourself in anticipation for such treatment being available later? Or is that not possible? Have you even looked into it?
Saw this on HN.
Live forever: Scientists say they’ll soon extend life ‘well beyond 120’