Most have developed through trial and error overtime.

People didn't reach at ideas like republicanism or democracy through accident after trying different things at random. They are founded on ideologies laid out by political philosophers like Aristotle, Rousseau and Benjamin Franklin. Hence why their foundational ideologies and principles remain the same.

Even revolutionary countries like France changed immensely from the first attempts to create the perfect society because it simply didn't work. They have a whole unelected house due to this.

And cars don't look exactly what mr. Ford was producing in 1914, hence by the same logic they were never designed from scratch.

Also, revolutionary nations are not a special case or an exception, they are the overwhelming rule. Almost every country in the world follows a system of government that was deliberately invented at some recent point. Including all of the most powerful ones such as USA, Germany, Russia and China.

Saying they were designed from scratch in the last 500 year is BS, as if nothing changed since then. Millions of people died in the process of getting government just OK.

Millions of people died because of power conflict, not to make government OK. Political systems in the world are a reflection of the underlying power dynamics between men, and the violent uprisings and wars throughout history reflect the struggle of different groups to reach power and install political systems that favor their own interests. Hence how you get a family cucking and brainwashing a whole nation into worshipping and serving them (A.K.A. monarchy).