Over sufficiently long time horizons, natural selection takes over. The dominant ethical belief will be that the right thing to do is to spread one’s own genes at the exclusion of everything else. We need to solve ethics before that happens, or otherwise prevent that from happening.
My main issue is that the ancestral environment or a historical environment had religions declare a similar goal and fail to favor the beliefs which you mocked. For example, The Bible had God say: “Be fruitful and multiply, and fill the earth and subdue it; rule over the fish of the sea and the birds of the air and every creature that crawls upon the earth.” In the ancestral/historical environment producing kids was bottlenecked on the ability to satisfy needs like food or housing, which in turn was bottlenecked on the community’s ability to guard resources, to transform them into useful outcomes and to avoid overexploiting the resources.
My main issue is that the ancestral environment or a historical environment had religions declare a similar goal and fail to favor the beliefs which you mocked. For example, The Bible had God say: “Be fruitful and multiply, and fill the earth and subdue it; rule over the fish of the sea and the birds of the air and every creature that crawls upon the earth.” In the ancestral/historical environment producing kids was bottlenecked on the ability to satisfy needs like food or housing, which in turn was bottlenecked on the community’s ability to guard resources, to transform them into useful outcomes and to avoid overexploiting the resources.