If you are looking for a religious discussion, I offer the folowing quote from a well know graduate of the US Naval Academy.
"History does not record anywhere or at anytime a religion that has any rational basis. Religion is a crutch for people not strong enough to stand up to the unknown without help. But, like dandruff most people do have a religion and spend time and money on it and seem to derive considerable pleasure from fiddling with it."
"Of all the nonsense that twists the world, the concept of 'altruism' is the worst. People do what they want to, every time. If it pains them, to make a choice- if the 'choice' looks like a 'sacrifice' -- you can be sure that it is no nobler than the discomfort caused by greediness... the necessity of having to decide between two things you want when you can't have both. The ordinary bloke suffers every time he chooses between spending a buck on beer or tucking it away for his kids, between getting up to go to work and losing his job. But he always chooses that which hurts least or pleasures most. The scoundrel and the saint make the same choices...."
Insisting that religion has to be rational is playing God in my opinion, however, I respect many people who belong to the atheist belief system, so I'll move on.
If the supposed religious prosthesis aspects of altruism you mention are removed, foundations for a successful society remain. Can you honestly say you'd rather live with a selfish individual who didn't wash, stole and told you lies, then a clean and honest person? What's true for the microcosm is also true for the macrocosm.
The scoundrel and the saint make the same choices................please explain.