Helix, what you seem to be ignoring is the effect of environment on human beings. Prior to the flood the earth was surrounded with a vapor barrier that eliminated and maybe prohibited the earth being bombarded with radiation. After the flood and the disappearance of this barrier the effects of radiation would be a new factor to deal with. Therefore, you are assuming a lot concerning the pre-flood gene pool.
Although your little essay is humorous and right on target regarding the lifestyles of the rich and famous, the same can be said for independently wealthy families outside of royalty. In Medieval Europe kings choose their brides not only from the daughters of kings but from the daughters of dukes, barons, earls, and others in the upper class who could bring lands, connections, and wealth under their control.
Eleanor of Aquitaine is a good example. She was the daughter of a wealthy and powerful duke. She was married to a King of France and a King of England. Her dowry, which remained in her control and therefore the control of each king she married was the province of Aquitaine. After her death Aquitaine became an English provence.
So not all kings and princes were married off to cousins and close relatives. Catherine the Great was not related to the Russian Czar Peter the Great. But her son was a lunatic. On the other hand Queen Victoria married her cousin and there eldest son was not the most intellectual man to rule the British Empire.
A lot of jokes are made concerning the Ozarks, but what can be proven is that inbreeding has caused major problems in portions of the population of the Ozarks. Incest is prohibited for sound scientific reasons that were not discovered until thousands of years after God gave Moses the Torah.
How much do you know about HIV? I discern from what you posted your knowledge is severly lacking. Although HIV became a pandemic in the view of American's in the early 1980's a search of medical records have uncovered facts that show HIV has been in the population of Africa at some level for more than 100 years. Since there are at least 10 strains of HIV and HIV easily and readily mutates it is difficult to believe that science will ever defeat this virus.
Lack of space on this forum prohibits a lengthy explanation and review of the medical histories that can demonstrate the truth I posted. However, one researcher obtained blood samples from a 1960's (if my memory is correct) ebola outbreak and tested the stored blood for HIV. 8% of the samples were infected. There is a case of the death of an Englishman in the 1950's that closely parallels a death from complications of HIV. This man had been in Africa and partook of the local women before he returned to England where he died a mysterious death.
HIV is viewed by most HIV experts as a zenotype, which means mankind was infected by contact with an infected animal, in this case an oragutan. Scientists are still debating if the virus was transmitted by eating infecting blood since oragutan's are a food source for some Africans. Monkey brains are a delicacy and the HIV virus can invade the brain. Then of course there are those who think HIV was transmitted to mankind in the same way syphulus was transmitted to mankind from sheep.
What is interesting about the AIDS pandemic is that living a moral sexual life could totally eradicate HIV in one generation.