I consider it to be unfortunate that the bulk of the pro-longevity aging research camp is focused on an inefficient path forward that will in the end lead to lesser benefits. It is their belief that this is the only practical way ahead: a laborious slog towards complete understanding of aging and metabolism, followed by an even more complex navigation through re-engineering that metabolism to age more slowly. The sheer scale and difficulty of that task is why many scientists feel that meaningful engineered longevity - more healthy years through science - is a long way away indeed.
This true in a way: extension of healthy life will be a long time coming if metabolic manipulation is the only path taken by the research community. Fortunately, metabolic re-engineering is not the only way ahead. It's not the most efficient way ahead either. The better path is to refrain from changing the way in which our metabolic processes work. Instead we should indentify the biochemical differences between an old, damaged metabolism and a young, healthy metabolism - and then repair them, thus reversing aging.
It is likely to be easier and less costly to produce rejuvenation therapies than to produce a reliable and significant slowing of aging. A rejuvenation therapy doesn't require a whole new metabolism to be engineered, tested, and understood - it requires that we revert clearly identified changes to return to a metabolic model that we know works, as it's used by a few billion young people already. Those rejuvenation therapies will be far more effective that slowing aging in terms of additional years gained, since you can keep coming back to use them again and again. They will also help the aged, who are not helped at all by a therapy that merely slows aging.
All that said, I noticed that Pure Pedantry is commenting today on an analysis by researchers Jan Vijg and Judith Campisi. It's a view from the metabolic re-engineering camp, dug in for the long, slow haul:
All in all, this a very good review that I recommend reading in its entirety. They strike a note of cautious optimism that I think is right on: we are learning more about this field but there is no justification for irrational exuberance.
Not on that path, in any case. It's hard to be hugely overwhelmed by progress that might, maybe, do a little good for young people fifty years from now. What is needed today is a determined effort to do good for the aged people of twenty to thirty years from now.