Regarding 3), how well someone's social strategies pay off is completely separate from their morality. It's irrelevant.
Just as a thought experiment: if there was little social cost to it, killing your competitors would probably be a very successful strategy. Would you go: "sure, he kills people, but it makes him very successful and we should give him kudos for that"?
Regarding your last statement, that "being nice and consistent" is a recent social norm, I call bullshit and citation needed.
Morality certainly has its merits – after all, it's omnipresent across nearly all human groups (that survived to this day). So it has undoubtedly played a central role in advancing humankind.
But please note morality is an evolved collective strategy as well, a survivor in an extremely competitive landscape. It's not "above" evolution (unless you're into religious metaphysical arguments).
If all its proponents "were killed" – your words; an unlikely proposition in my estimation – then yes, that would be it for morality. Something else would take its / our place, but the world would still go round.
> But please note morality is an evolved collective strategy as well, a survivor in an extremely competitive landscape. It's not "above" evolution (unless you're into religious metaphysical arguments).
I don't fancy a debate right now, but I feel I should point out for observers that this is a minority position in the philosophy of ethics (for atheists and religious philosophers alike). At the very least it is possible (and common) to be a moral realist without making "religious" arguments.
Just as a thought experiment: if there was little social cost to it, killing your competitors would probably be a very successful strategy. Would you go: "sure, he kills people, but it makes him very successful and we should give him kudos for that"?
Regarding your last statement, that "being nice and consistent" is a recent social norm, I call bullshit and citation needed.