IIRC, one of the "essential aspects of happiness that the founders clearly had in mind" was political control resting in the hands of white, male, property owners. Keeping women and Blacks in their place was a source of great happiness for them.

True, but the founders were of their time and their ideas, while limited in scope at first (see 3/5 clause) made it possible to create a country that could grow, learn and eventually get with the program in terms of the meaning of “We the people.” I still consider it a miracle that there was that much intellectual firepower in the room in Philadelphia. Similarly, the greatest amount of intelligence ever gathered in the White House was when Thomas Jefferson dined alone.