Thank you for the reply.
However, I think you misinterpreted what I was asking for.
I am asking for a future hypothetical where unlimited funds are available.
Of course that selective destructive/regeneration capability is not available today. I'm speaking about whether it is theoretically possible. On that front, I'd like to see proper critiques along the lines of what biological problems might be posed.
Also, the pixie dust is not a scam, as was often portrayed. The fingertip stuff was 4 years ago. It's since been used in regrowing muscles and skin in soldiers. However, I don't want to focus on that, other growth factors probably exist too.
The above in one sense has to exist somehow, because regeneration has been observed in animals like salamanders, but even more importantly, humans grow from a single cell. So biological mechanisms exist for growth. Pushing them to do so again, while destroying aging parts, is what I'm looking to explore.
So again, I reiterate, I'm looking for more than simple statements of "it isn't possible etc.", but more detailed discussion of the issues. And also, there is no limit on funds. So questions of decades vs months are essentially irrelevant. What you could do in decades can usually be done in months if the work is parallelized and done on a large scale.
Thank you for the reply, but I'm looking for something more substantial. (This is an initial brainstorming, from which proposals will be discussed with open-minded funders. Everyone stands to benefit if this goes anywhere ).