Re America: that sounds like exceptionalism to me. It's not an outlier. A bunch of rich dudes wanted to avoid taxes (fair enough), and to continue slaving and stealing indigenous land.

Plenty of countries that used to have dictators (absolute monarchs) were able to limit them to merely symbolic figures, and bring in constitutions and strong parliaments. Some of these were also revolutions. See most of Europe and their colonies. Yes some have since regressed, but there's nothing particularly special about the USA besides the fact that it didn't have quite as much entrenched power, at first, and virtually unlimited ability to expand. So it was special in terms of it's early flexibility, but ever since it expanded to fill all its available space, seems to be pretty non-special.