Otherwise, this is what peaceful cooperation looks like (I’ll give you this in exchange for that, where obviously the one with more desireable goods or services to trade will survive).
Most cultures have very strong social mores that sanction against hoarding or even general unwillingness to share. It's not THAT beyond the pale. What makes it hard is when society becomes disconnected enough, and community bonds get weak enough that social mores no longer bind behavior.
And from the perspective of the victors, it will be a better result, because winning guaranteed survival, whereas cooperation is essentially a lottery. So anybody who has a better chances to win a conflict than a lottery would choose conflict, if they are deciding solely on utilitarian rather than ethical grounds.
(A simple thought experiment: imagine there are 10 equally capable competitors, each needing 2 units of resources to survive, and there are only 10 available globally. Under cooperation, 5 competitors will need to be sacrificed, but 5 will live. Under competition, all 10 will perish, each holding their hard-won single unit of resources.)