Military service is traumatising, but can build up a nest egg of funds, so to speak. If your trauma doesn’t turn into a self-reinforcing cycle, you’re in a better position than most in our society (materially, not morally). It lends itself to falling in one extreme or another.
That said, I imagine there’s a decent number of people who get regular jobs in the middle that you never hear about. Just the people at the bottom get the whole “they sacrificed their mental health and their life, why can’t we help them” signal boost
I assume closely related hominids which are now extinct. Neanderthal DNA is present in current human strains, which means they didn’t even speciate (though potentially successful gestation was rarer).
Why am I writing like an alien nerd observing humans?