These things won't happen eventually. Yet future generations will take education, health and morality more seriously than we do.
We shouldn't punish children? Even for things they clearly understand are wrong?
This applies to all moral progress. Any prediction about morality that doesn't shock at least some people is unlikely to be both true and important.
Also, would some acts, like murder, still be punishable? Or are you imagining a shift so deep that no one would need to be punished.
I doubt that judicial punishment of strangers is going to end anytime soon, but note how different that is to punishing a family member.
However, now you mention it, there is an interesting similarity. Why does punishment happen? Not for the reasons most people think. For instance, it doesn't (and can't) transmit moral knowledge from the punisher to the punished. Neither does it reliably cause obedience.
In reality, society punishes criminals in order to prevent greater suffering in the form of larger scale rioting and madness.
Similarly, parents punish children to prevent themselves from going mad. But if knowledge spread of how to be a better and happier parent then this sort of punishment would end.
Such knowledge may already exist in basic form:
http://www.takingchildrenseriously.com/introductory_articles...