Morah Rach
Sure things change but then again the Torah never promoted Men taking more then one wife as the “ideal” rather the ideal was always Adam and Chava a monogamous relationship. There are many sources for this ex. why were Rachel and Leah not buried together with Yackov in the Mearas HaMachpala.
However the Torah on down through Chazal have promoted corporal punishment as an effective chinuch tool.
Furthermore on a practical level we have seen that the more certain methods of chinuch are utilized and “old” methods of chinuch are thron out, the more blatant the collapse of chinuch becomes.
Slowly as Public School methodologies are brought in to Yeshivos the results of PS are unfortunatley becoming rampant as well.