For their own good: locking children up in schools; telling them what to learn; coercing them in the name of health and education; punishing children at home.
These things won't happen eventually. Yet future generations will take education, health and morality more seriously than we do.
It sounds crazy, doesn't it? Of course, the idea of not punishing one's wife after she had done something which she understood to be wrong, once upon a time, also sounded crazy.
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.
I can, in sci-fi sense, imagine a world where we wouldn't need to discipline children, but it would take some pretty fundamental changes in our understanding of parenting techniques and probably involve some technology that doesn't exist today. That puts it pretty far away from "stop beating your wife" which just required you to... stop beating your wife. Are you thinking disciplining children instead would be a simple shift from today?
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 believe in gradual change. Ending the extrajudicial punishment of children is not such a big step, because it entails only a small extension of human status (having already incorporated women, slaves, foreigners, etc.)
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.
These things won't happen eventually. Yet future generations will take education, health and morality more seriously than we do.