Evolution has not solved the principal-agent problem.
> What is enough today will not help you survive tomorrow's famine.
Tomorrow's famine will be caused by you (read: those behaving as you describe) not knowing when enough is enough. Best preserve what we have, rather than waste it all in a frantic bid for number-goes-up.
Maybe it's moralizing, but I don't think it's wrong. I'm using the same model as you, after all, only I'm applying Kantian ethics instead of unconsidered egoism.
• If you wish yourself maximal reproductive fitness, then all humanity will be your descendants, and the next few centuries of all human interest is your interest.
• The iterated prisoner's dilemma is a classic economic argument, by which Tragedy of the Commons-type behaviours can be averted. (Garrett Hardin's 1968 paper is a load of nonsense.)
I'm not sure what would contrast my earlier "leftist moralizing", because I have absolutely no idea what a leftist is.
> Maybe it's moralizing, but I don't think it's wrong.
Religionists never think their religion is wrong. But I don't belong to your cult.
> because I have absolutely no idea what a leftist is.
Leftists never have any idea what a leftist is. But I don't belong to your cult.
> Tomorrow's famine will be caused by you
Possibly. Or maybe it will happen anyway.
> (read: those behaving as you describe)
That's mostly leftist moralizing on your part.