I am pretty amused by genetics in the thought that things improve with every generation or that getting a certain gene pool will mean success. Take for example when a horse with a successful track record finishes their career people pay big money for the breeding with that horse. Case in point I've seen a lot of horses with Seattle Slew lineage and none of these horses were great achievers. They were horses of good confirmation but none of them ever had an impressive track record.
The same goes for people. Take John, Robert and Ted Kennedy, all were big deals as was their father. Their father's money and influence helped the three become very successful, but each generation after that has significantly diminished. The same with Prescot Bush. He had a son and a grand son that became Presidents of the United States, but it strongly appears that each generation since Prescot has a diminishing intellect.
I guess it's really more about money and influence that it actually has to do with a continued genetic trait for success.