Quality of Population is Everything, or Nearly So...

To determine this, that is, whether cultural changes from without may be the more important causal factor one should look at historical comparisons
in terms of miles, and relative cultural penetration.
If we have cultural explanations to give the leading role to, and leaving little
or nothing for genetic difference to account for;
how then could western culture with great advances of technology and science to show
IN SITU, even routinely at many of its far edges, have been able to penetrate thousands of miles, in 100 or so years,
where it had the same genetic substrate
to ride along on, and not be able to penetrate even
a few miles off the coast, almost anywhere in the tropics in hundreds,
even 500 years? 500 YEARS is a LONG time, and cultural influences are often mobile at speeds so high, and vaulting gulfs so profound between societies, that it cannot be assumed that they need, for example, military interventions, to travel long distances. If one says institutions have explanatory precedence over quality of population, one only has to observe or project the replacement of superior institutions' personnel with that of the world average or below, to see that the quality of population is well-nigh everything. No institutional set-up can override the effect of very low quality of staff.