...good post! In early America, the means of great volumes of production for per capita use needed to be built, for the most part. That’s probably one of the main reasons that America had good leaders then. Bullies want fast, easy wealth for power. The other main reason was the predominant early American Puritan culture (morality).
I would put this first, and foremost, as to why America had good leaders in its early days.
That, and the fact that suvival required that every man make himself useful.
Jamestown almost went the way of the Lost Colony of Roanoke until it required that every man work.