If we look carefully at the data, there are two things that may come as a surprise:
1) Most of the significant figures of literature came from the Southeast and (mostly West) Midlands, but few came from the relatively wealthy Southwest (eg Bristol) and East Anglia (eg Cambridge), nor from the poorer Northwest or Northeast.
2) It's more balanced for science figures, but East Anglia, the most Germanic part of Britain, still performs very badly, despite its proximity from London and the presence of Cambridge University. That
is odd.
As for Celto-Germanic areas performing better economically or scientifically than more purely Germanic or Italo-Celtic ones, this phenomenon has long been observed. In Germany, the wealthiest regions are in the west (Rhineland) and south (Baden-Württenberg and Bavaria), which have mixed Italo-Celtic and Germanic ancestry. Austria and Switzerland are even wealthier and even more mixed. In Italy, the wealthiest regions are in the north, where Germanic, Celtic and Italic ancestry come together. In Spain, Catalonia is one of the wealthiest region (if we exclude Madrid as it benefits from being the capital) and has the highest Germanic ancestry.
The economic backbone of Europe is the region almost exactly at the limit between Italo-Celtic and Germanic regions. It has been dubbed the
Blue Banana due to its shape on the map. I think the map should include a bit more of Austria and maybe also the Rhône-Alpes region in France. It does match to some extent the more densely populated parts of Europe. But that makes me wonder too why these regions in particular became more populous over time? It wasn't the case at all in ancient times. Is it the hybrid vigour of the population mixing that enabled a more vibrant economy as well as a higher fertility rate?
There are many possible reasons, but hybrid populations may benefit from the fact that some individuals get the best alleles of the two (or more) source populations. But inevitably some people will also end up with more deleterious alleles from both populations. After centuries of natural selection, the overall population would have naturally pruned more of the bad alleles and conserved more of the advantageous ones than in an unmixed population. In other words, hybridising populations accelerates the process of natural selection.
I have long wondered if the blending of population was one of the causes of increased socio-economic inequalities. Countries where populations have mixed relatively recently, like in the American continent and Australia, have much higher levels of inequalities. That is also the case in much of Sub-Saharan Africa, where tribes didn't mix much with one another until the 20th century when rural exodus forced people of different ethnic backgrounds to mix in cities.
In contrast, more homogeneous populations, or at least where the blend has been allowed to stabilised over many centuries, like in Scandinavia, Finland, the Czech Republic, Slovakia, Slovenia, Hungary, Albania, Belarus, Ukraine, Korea or Japan, are more egalitarian.