I don't know about you, but there was a limit to how how bad my parents could make me feel through non-abusive consequences. There was always an emotional weighing of the impulse to misbehave versus the punishment that would follow. As with most children, the deprivation of privileges my parents could inflict on me was generally severe enough to outweigh the emotions that drove me misbehave, but when a kid's impulses are too strong, I imagine his feelings of rage and defiance can outweigh any non-abusive punishment a his parents can inflict. These days such a kid is destined for an institution, even though a few beatings might make him a functional member of society.

That said, I think it's for the best that physical abuse is criminalized, because I don't think human beings can be trusted to use it judiciously. Like you pointed out, when accepted, it is used inappropriately and destructively much more often than it is used appropriately (hey, just like guns.) However, one consequence of giving up corporal punishment is that some (very small) subset of kids will be deprived of punishment that could have set them on a better course, and in the end society will resort to violence to control them, violence carried out lawfully via the justice system.