I'll give you the "do your job" point. The issue, for me is, while doing our job as expected, over time the conditions of employment become altered, or don't keep up with the market. In effect the terms change. Now we do have the option to leave, when that happens, but that kind of relationship offers little in the way of consistency or stability, for the employee.
Your wife likely prefers a contract. You, on the other hand, may not. Figuratively speaking, of course.
So what your saying is a marriage is a contract well how misinformed you are biblically speaking a marriage is a bond between a man and a woman not a contract.