Eh, that kind of tech will never be available to the masses. Catastrophic climate change and overpopulation/resource depletion in the second half of this century will place the ceiling on technology at whatever can be produced in the next 20 years or so, I'm guessing. We know a lot about genes but not nearly enough to start hacking CRISPR in a marketable manner. However, I can imagine a post apocalyptic future where humanity has been stratified into two classes: organic humans, clinging to life at the poles, and gmo humans, modified to survive low oxygen levels and wet bulb temperatures, with dramatically reduced metabolic needs that allow them to live in areas of the planet the others can't.