Corporal punishment doesn't work in any other walk of life. Nobody whips their employees if they fuck up. A professor can't slap his student for not paying attention during a college lecture. But it's somehow okay for kids. Never got that. It always struck me as an archaic method of punishment rooted in ignorance.
Schools in the south still have the ability to paddle students who misbehave. (Not colleges mind you)
An employer expects you to behave like an adult. If you misbehave they will just punish you be firing you, taking pay, etc. Which is much more effective on someone who understands the importance of money.
A college professor can have you removed from the class. Makes it hard to graduate on time if you dont behave and keep getting dropped from classes. Also a waste of money if you/your parents are paying for it.
Are there other ways to punish children? Yes. Do they work? Yes. Do they always work? No. Spanking, to me, is more of a last resort no other punishment worked approach. Thats how it was for my parents raising my and my brother. My granny didnt jump up to whip us all the time either. It was always last resort when our hardheaded asses refused to listen.