There are cultural reasons and Biblical reasons that make it difficult. Culturally, the defining spirit in America today is self-determination, not submission to the will of another. The ultimate value in America is the unencumbered self. Anything that enhances my individual liberty to do as I please is good. And anything that encumbers me and limits my ability to do as I please is bad.
Self is king.
And autonomy is the highest law. Another part of our culture that makes this text difficult is that authority and power have been so often abused that there are legitimate misgivings about making obedience and submission the norm. And what they have in mind in part is the abuse of power to manipulate and coerce and use people to enhance the leader's status and stroke the leader's ego and sometimes line the leader's pocket. So preaching on this text in this atmosphere is like standing up the Sunday after 60 million people have watched police beat up Rodney King and preaching on submission to your law enforcement officers. But there are more important Biblical reasons for why this text is difficult to preach on - that is, why it is not easy to know exactly what this obedience should look like in actual practice.