This is a biblical principle as well:
[BIBLE] John 9:21 [/BIBLE]
The point is simply this: there are those in every society who are "spoken for," and those who "speak for themselves."
In Abraham's circumstances, there was two basic choices among those who had some kind of voice: conform to the God-given directions spoken by His minister, or be on your way. There are other masters, other opportunities, and other gods to claim you, or for you to claim.
The advantage of circumcising the little baby was: that he had nothing at all to say for himself--he was as helpless a picture of man in the fallen state as you can find. He was acted upon by God, through his minister. If there were grown men or even boys who balked at the requirement for joining the covenant-people, they would not become members but remain strangers.
Would a man put his own son out of his house for not following Jehovah in circumcision as he did himself? I'm willing to bet that was determined on a case-by-case basis. However, that man or boy would have no place in Israel, unless and until he was publicly joined to the nation. He was effectively excluded from the life of the nation, however much he benefited peripherally.
In Abraham's day, the choice was stark and simple. One man, one family, one house, a sojourner and a pilgrim in the world. One was either committed to the Covenant mediator, or he was adrift with the rest of the world.
In the land of Israel, many centuries later, the context was different, with the same principles at work in a more settled condition.
In our day, we make do with our own cultural mores, as we are often obliged to do. In the USA our children are ours until the State decides they are effectively (legally) emancipated at age 18. Our relations to our live-in parents, etc., is a whole other dynamic.
The simple answer is: if we are found in yet another cultural situation, where the answers to our questions as "what is to be done," must be reordered, then we will do so. Servants such as constituted households in former days are no longer normal in our culture, and perhaps not any place. But in the days of the apostles, it was not abnormal at all. And time could bring "strange" culture back around again. Good thing we don't live so long.
We live and work within the providential historic circumstances where we are born, or to which we move in our short lifetimes. The Scriptures compel us to rigidity in certain things, and dynamism in others, as it addresses man in timeless fashion.