I think what you are missing is that a lot of what we have learned about the universe turned out to be much simpler than one would have thought. A World with roughly 12 elementary particles was beyond the wildest dreams of some older civilizations, say, the Arabs in the 14th century. We have come to terms with the idea that reality is by and large summarizable by a few principles. So if morality turns out to be Real, it will probably also be somewhat simple. That's the intuition.