Exodus 21:4-5 (KJV) 4 If his master have given him a wife, and she have born him sons or daughters; the wife and her children shall be her master's, and he shall go out by himself. 5 And if the servant shall plainly say, I love my master, my wife, and my children; I will not go out free: 6 Then his master shall bring him unto the judges; he shall also bring him to the door, or unto the door post; and his master shall bore his ear through with an aul; and he shall serve him for ever.
To me, this is proof that life just isn’t as simple as you want to believe. It doesn’t give the option to work for seven more years and walk away with your wife and kids.
That is one option for how to do things, sure. However, are you trying to tell me that you see no precedent in the Biblical world where one free man can redeem a slave from another? These laws do not work in isolation, but in concert with one another, and should be done in the overall spirit of loving God and loving our neighbor as ourselves. So, if you think the best way to appropriate them is to imagine the most negative outcomes, I think you are off the track a bit. Halachah could be described as the art of walking these matters out. Thus, if we are to walk them out according to the greatest commandments, we must pursue the most loving way to reconcile the laws of property with the laws of marriage. Can we choose to be harsh in our applications? Sure, but does that fall in line with the purpose of the law? No.
Indeed, reconciling God's laws with the laws of men can be difficult at times, but we should take inspiration from Moses' parents who did not, in fact, break the command to throw the male Hebrew children into the river. Moses went into the river. They just happened to be also interested in the preservation of life so they furnished him with a boat and a guardian.
In short, it would be silly to think that the other Biblical laws do not apply. Can he become a lifelong servant? Sure. However, we also have the record of the price of a female slave. We also have the concept of the Kinsman redeemer. Go on down the list. Above all, we have the laws of loving God and loving our neighbors. On these two hang ALL the Law and the Prophets.
Simple and uncomplicated? No. However, I would suggest that I am not the one trying to simplify a complex matter of law. In no society on the face of the earth do laws operate in a vacuum. They interact with all the other laws and statutes of a given society.
I mentioned seven years. If that was worth, to the master, the value of the girl, why not? If she is his property, what prevents him from selling her, or ever choosing to give her freely? He might accept only the silver valuation of a female slave... or perhaps he would like an extra field for growing his barley. Alternately, he may choose never to sell, hoping to acquire the male forever as well.
On the other hand, let us look at another Scriptural concept: we are not to harvest the corners of our fields, yes? Well, how big is your corner? The last stalk of corn, right where the two edges meet? Or, if the man has a good eye, and not an evil eye, can he choose to make his corners large and provide abundantly for those in need?
If the master is to supply the former slave liberally from what is his property, and he is generous, is there anything which prevents him from giving the woman freely? She is his property, he can do as he wishes.
All I am saying is that there are options, shown by the other laws and principles of Scripture, besides necessarily choosing between wife and freedom. Those options will probably bear much healthier fruit in a society.