[ 20/6/20 ]
It seems clear to me that the answer is yes, and it is a very complex suite of issues that need to be mitigated to do so.
If you look purely at cellular life, every cell alive today has a real claim to being the first cell. Therefore the default mode of cellular life is indefinite. (Whenever a cell divides, both cells are essentially identical; both contain old and new parts in roughly equal measure.)
When you look at cells in complex animals like us, then the story gets more complex, as the complexity that is us is mediated on billions of cells with identical DNA but modified sets of gene expression modifying factors, most of which follow some sort of fractal pattern.
So resetting all those modifying factors to some set of conditions that signal the organism to be a 20 year old body is likely to require many levels of modification (some within cells, some between cells) and the technology to achieve that does seem to be on the not too distant time horizon, provided we don’t exterminate ourselves before then.
It has been clear to me since completing 3rd year biochemistry at university in 1974 that indefinite life extension is technically possible. The question that immediately occurred when I realised that was: what sort of social, political and technical structures are required to give individuals with the potential to live on indefinitely a reasonable probability of doing so with reasonable degrees of freedom?
That is problem space at least as difficult as resetting our biological clock mechanisms periodically; and it is clear that markets are not a useful tool in doing that.
Looked at systemically, the competitive contexts engendered by markets is antithetical to any real degrees of security or freedom for the vast majority.
Real freedom demands a cooperative base to the social structures present, and we can build as many competitive structures as we want on the cooperative base. But trying to build a system on a competitive base always reduces real freedom to some set of minima, and increase risk to all – so is counter to the principal of longevity or the value of life.