The final solution

It is often said that the universe does not care.

But it does: try breaking quantum mechanics. You will fail. The universe cares about quantum mechanics.

We care too much, about the wrong things, but we are getting better.

The evolution of morality is effectively a convergent dance, with what we care about converging towards what the universe cares about. With accelerating abstraction, we encode what we care into what the universe cares.

• The universe cares a lot about obstructing prime factorization attempts, so we encode trust into the RSA crypt.
• The universe cares a lot about numerical consistency, so we encoded fairness into certain processes of interpreting and using statistical data.
• The universe cares a lot about thermodynamics, so we encoded parts of our life-preserving morality into rules on energy use and greenhouse gas emission, forced by the looming climate change.

There are hints of this kind of moral development in one person's life. As a person develops, they adjust their expectations to reality, including their morality. No longer do they demand the impossible, such as for friendships to last forever, or for childhood to last forever, or to blame others for things they could not have foreseen, or to demand "unreasonable" effort from others. In short, they learn to be reasonable. How "unreasonable" is unreasonable, of course, is finely calibrated to reality, and changes from time to time, with new information technologies, heat engines, social conventions, and so on, changing the boundary of the "reasonable". 

They pretend that it's consistent with previous moralities. That in developing such a morality so finely attuned to reality, they were merely remembering what morality they once saw in a higher plane of existence (like Plato claims). Or perhaps they claim that the seed of morality has been buried when they were just starting to think, and they were simply growing out the full branches and leaves of the tree of morality.

However, this explanation is a fabrication. There is no Platonic plane of existence, and there is no seed of morality. Instead, morality is like water, taking the shape of its container, which is (material, social, informational) reality.

Now imagine scaling this up to moral development in humanity's history.

Complex encodings develop to close the gap between our hopes and the world. From our dreaming brains, tentacles of thought extend out, bifurcating, reweaving, gripping reality by a thousand little physical contacts.

The perfection of moral encoding transforms morality into equivalent natural laws. At this perfect point, we would finally stop striving to be moral -- we would have no choice but be moral, when morality (after encoding) becomes a subset of physics.

The end point of moral development, then, is the end of moral striving. Moral thoughts and actions become compulsory, automatic, and the world is beautiful just the way it runs.