It’s an oversimplification and is not how ecosystems work. I trust ecology more than simplified conjecture. Civilization is an ecological special case with a unique set of courting and mating rituals intrinsic to the specific civilization. The special case rules of the courting and mating behaviors result in much more chaotic genetic drift than non civilization confined populations. Civilization has resulted in human forms as unnatural and unsustainable in nature as the many forms of dogs with unhealthy morphological features. Just as a bulldog would never survive surrounded by wolves, few humans today would survive reality. On the other hand, bulldogs are very attractive to other bulldogs, and as a wiser generation observed. may still breed with shih tzus to make bullshit puppies.