The consequences were not unavoidable enough. A lone savage could survive, so the incentive to not be a dick was not really sufficient.
To survive in a genetic way, which is the only relevant way we are talking about, you need yourself to survive and your newborns, and their children and and and.
That will require not only great skills. But great companionship.
And this companionship had to be played in a group of no more than 100 or 300 individuals for MILLENIA. I am not kidding with the big letters.
Whatever made the human breed - it was people most of all skilled to integrate into a group. Beyond all else.
Whoever's genes will master an apocalypse. It, at least, will ALSO be those genes favoring your butt to get cover in a group, one way or the other.
Loners die
Which you said. But I don't think you realize what that means. We eradicated genetic mass loner strains a long time ago, IMO. And what these days seems as misfits is OF COURSE no measure. Our way of life is totally detached from what constituted a humane life, originally.
So it stands to reason that whoever held the handles in an apocalyptic future, it would be far from those today.
Plastic and water hormones.
Average growth rate of males.
It is just amazing what is going on in the world. And where we came from,