We consider and test alternatives for everything we do. The biotechnology, of course, is the result of thousands of experiments. Nothing that happens while you are unconscious, nothing we do to your genes, thymus, immune system, every aging part of you that we have the technology to improve, hasn't been tweaked as much as our considerable expertise and funds allow. But we don't stop at that.
We could do it all in twenty hours, but customers pay much more if they have to be unconscious for three days, and, technically, the tissue donor could survive the procedure.