You’re right of course: there’s no guarantee that inbreeding will get the results you desire. However it increases the statistical odds of getting the traits exemplified or reduced in the offspring, because of the controlled environment (so to speak). Centuries of animal and plant domestication are an open testament to this.
Again genetic diversification has its own perils. As an example: Sickle Cell Syndrome. In times past it was a trait found exclusively in Africa or Arabia (depending on whose research you read). However as racial migration and interbreeding increased through the centuries, this disease has found its way into other ethnicities (I’ve read a report of a rare happening with Chinese children; National Geographic if memory serves correctly). The increasing population of “racially mixed” children through out the United States and Europe, only boost the prevalence in family trees that traditionally would not have been threatened.
Now far be it for me to claim diversity is something we should avoid ¬ñ overall the gains are greater than the losses (and I myself am the product of two ethnically diverse parents). However the automatic assumption that “outbreeding = good” and “inbreeding = bad” is not true. It’s all dependant on the genes and traits. A gene pool that’s immune to a specific disease, can remove that immunity by breeding with a gene pool that is not. Of course a gene pool that susceptible to a certain illness only increases that weakness by not introducing more immunity.
Ultimately it becomes a discussion of what you’re looking for in the descendants, and how long the inbreeding/outbreeding takes effect. Biologically humans are no different than any other creature on Earth, and if you’re unethical enough you can produce a reliable number of offspring with the desired traits you want. The NAZI’s weren’t totally wrong they could produce their nation of “blue eyed and blonde hair” people. It would just take generations of dedicated monitoring and ruthless culling of the undesirables… something we’ve long done with roses and dogs (and obviously something Hitler had no problem with). Of course what inherited illnesses and weaknesses this forced ethnicity would have had, could probably fill entire libraries… but it would have had it’s trait strengths.
That being said: I think it’s impossible to breed a “perfect human” without artificial genetic tampering (and obviously more advanced technology). Of course the definition of what’s perfect is also suspect to social perception… what people considered a perfect human 1000 years ago - physically and intellectually - are certainly not the same as today. And then of course, there’s the whole question if the human form is even best for humanity… if we could genetically manipulate our physical form, I doubt we’d be Homo Sapiens if they were looking out for the whole survival first thing (compared to what we find visually appealing).
In the World of Narg, all girls would be born as twins and males would only make 30% of the population. I haven’t figured out how the logistics of it all would work though.
