> We had a long experience with such a system.
No, your ancestors had experience with such a system. They are long dead, and the struggles they faced and lessons they learned have been abstracted and bowdlerized until all we're left with is a parable against the abstract idea of a dictator.
George Washington wasn't fighting an abstract dictator. He was fighting the British Empire, an actual existing enemy with an actual ruler, with millions of people on every sides who either supported or fought against it for their own reasons. I can't even pretend to understand the issues they faced, but I do know that you cannot summarize them into a single factor.
Consider a much simpler event, like 9/11. If anyone says, "There's one reason why 9/11 happened, which is X - this is why we must never do X ever again," how much would you trust such an analysis?
That's all I'm saying. My Korean experience tells me that anyone who says it can be reduced to a single factor, or even a major factor (the size of the government), is selling snake oil. Of course, that doesn't mean I know a universal solution to avoid tyranny. If there was such a solution, mankind didn't discover it yet.