There is one part of the Birthright cosmology which as it stands is absolute,
unadulterated, bullshit; The TOTAL extinction of the great established (old)

Let me illustrate with a real world example. The Plantagenant Kings of England
ceased to exist in the male line in the late 1400's. Yet millions of people
are descended from from one of them; Edward III. (Through various female
offspring obviously)

Now let's look at this from a Birthright perspective. If Edward III had had a
birthright bloodline his direct male line would have died on Bosworth Field
with Richard III but so what ! Daughters spread out the bloodline just as well
as sons. As long as the "royal" daughters had married blooded individuals
and were fertile their bloodline would, by the games definition,
predominate. IT

The Plantagenants were preferred marriage partners for only 300 years. The
Roeles would have been such for 1000 years. So this dog won't hunt.
(American phrase of Southern origin meaning; this idea is not practical.)

I have already given the only two practical ways of explaining this phenomenen;
1) low or nil fertility. Not mentioned in the literature.
2) blood dilution through bloodless marriages. Highly unlikely.
Note that ugliness would not explain it. 1000 years of assassinations or
Deity meddling could do it but neither of these are mentioned in the
literature. So the question I pose is; what is causing this ? Or is this
just a big boo-boo.