A selfless individual will choose the winning solution to the Platonia delemma.
Will your “good person” The more selfless the population the greater the potential payoff for a cheat.

This is especially true as the potential rewards for cheating climb.

You assume that if we learn biology, human psychology, and try not to cause harm to sentient life, we will become selflessness. The latter does not follow from the former. To be truly selfless we must ground our identity in something other then ourselves or our posterity. We must live for something other then ourselves. The broader that choice of purpose is the better. God is the broadest possible choice and the only one that allows for the formation of true selfishness.

I do not expect us to see eye to eye on this issue. However, once you understand this point you understand why acceptance and faith in God is more important to salvation then prior sins and good deeds.