How to keep the money in the family

Fortunes dissipate in the third generation, that is a well demonstrated fact. Dynasties last four-five generations, even adopting extreme endogamy like Egyptian Pharaohs or Alexander's  Διάδοχοι successor dynasties, they are unsustainable. Lasting elite groups in history are India's Brahmins (who maintain their status over two thousand years) and the Jewish people (upper middle class everywhere)  and possibly, European aristocracy (that emerged with Pepin of Landen and ruled till WWI - see pic of a representative selection of nine kings*).  In more diluted way, it appears that the Norman fighting elite that entered Great Britain maintains its position to these days. 

The "secret" of a lasting multigenerational elite position is moderate endogamy. Marrying within the group,  mostly among successful members and constantly dropping off the unsuccessful. It is almost impossible to follow this rule for long because humans are by nature promiscous and unattracted to the familiar (which explains the rarity of fertile sibling pairing). The dropping off happened naturally during harsh winters and famine years, no one was forced to do morally repugnant selections, but now subsistence is ensured. 

The opposite of "keeping the money in the family" i.e. losing elite position in one or a few generations, is exogamy. Mixing between human lines, which happens to be the norm in recorded history. I have seen that in the Dominican Republic where the Spaniards have completely dissolved. It is happening all over the world. That's how it is. Can't do a thing. Accept and enjoy.  

As an old man nearing the end of his life, with neither fortune nor position to transfer to the next generation, I don't care and lack the ambition to change reality. All I want now is to avoid depression/indolence and complete this Ramat Gan job, and write that article about sewage pretreatment that I am dodging for months. 

(*) None of the faces radiates intelligence, or am I prejudiced against antisemites?