Self-evident to whom?
I would say that "better" is subjective. Morality doesn't have to be premised on improvement, merely what the many deem fit.
I had this same discussion yesterday with someone in the man/machine thread. If you think "better" is subjective, I don't particularly envy your state of mind. Not to try to attack you or anything, but you must live in a world of utter confusion. I know because I've been there.
What you're plainly telling me is that slavery and freedom are basically equal because it's all just subjective, just an opinion. If someone THINKS human sacrifice is good for them, then it IS good for them. That's what you're telling me. And I can
almost see your point. But not really.
There is right and wrong. There is better and worse. Just LOOK. I have trouble explaining it otherwise, but I'll try. It IS self evident, though. That the world is better and happier now than it was in WWII is pretty damn objective, if you ask me. No, I don't think science has a perfect way to prove that yet, but I think it is something that is possible. If you disagree, look up that 3 hour documentary about the Eastern front in WWII, I think it's on youtube. There you'll find a picture of true misery. Things are better now. It's self evident.
Specifically though, the problem with your case is that we actually have an objective programming. There is a right and a wrong way to make people happy,
biologically. All you have to assume is that suffering is bad and happiness is good. Honestly I think that's a safe enough assumption to make. The systems you listed in the OP all have in common that they enable people to choose what makes them happy and protect their own happiness, which is philosophically good, but also historically good. Life under these principles has always been the more prosperous way to exist on this planet.
I could probably go on, and will continue to think on this question throughout the day. Maybe I'll add more later.