That's the promise discussed, aye. Yet that's not a new intent, far from it. As another commenter notes improvements frequently extend a poor quality and phase

That's the promise discussed, aye. Yet that's not a new intent, far from it. As another commenter notes improvements frequently extend a poor quality and phase of life, or an extra decade parked in a care home. I can't help but expect that despite intent this will end up achieving more of the same... As for naive youth, I'm less sure - just a decade out of twenties leads to different outlook and choices. I suspect the people who keep that naive youthful mindset, are one of the very rare few who manage that naturally. I suspect this is the hard part. A octogenarian, with the health of a thirty year old, is still likely to have an elderly - or extremely experienced if you prefer - outlook. Will that lead to apparently 25 year old octogenarians yelling at actual 25 year old's to turn off the infernal noise? :) We certainly grow old more disgracefully than our grand or great grandparents, who seemed positively old at 40. That seems to be societal rather than longevity or medical. I suspect there isn't much more to come there.