Agreed, which is why we’re likely to use CRISPR or something like it to accelerate the process.

It’s not as simple as editing genes. You have to understand the development of the organism in question. And also any tangential things the genes in question may do, some of which might not manifest themselves until puberty, adulthood, or even old age. We’re generations away from that kind of knowledge about humans.

Changing how an entire species is adapted for a planet is far different from selectively knocking out a gene here or there that has mostly deleterious effects. We can’t even safely do the latter yet in humans, let alone the former.