But with the husband as the head, a decision can be reached. He may decide that his preference is best, and do that, or he may decide to do his wife's preference out of love for her. But either way, a decision is made. And his wife chooses to submit to that decision, whether she likes it or not - her input has been considered, and the time for argument is over. They can now move forward as a team. She can support him with paying for the new car, or she can politely keep her mouth shut when the cheap car breaks down and simply help him get it fixed. But either way, they're a team.
That's the primary purpose of patriarchy, in my view. Achieving unity and peace.
Thank you @FollowingHim
In the end, it's about hierarchy, structure, roles...order.
The biblical, patriarchal model is about being the head, not a two-headed monster. Its like the Truman quote: "The buck stops here."
It's not about being a soft, cuddly teddy bear that always acquiesces. Sometimes no is the best word in the English language. If it's used in love, it can be powerful.
There's more, but I'll let the wisdom of others come forth.