I would tend to agree, but some people tend to excel at one subject, say history, but are really bad at math. By math, I don't mean problems like "10 people are in a bus, 5 left, how many people are left on the bus. I mean math 10^8 x 9/10 = x. However, this isn't just IQ alone, because of how bad modern education is, they might've just either not cared in school, or not been taught how to do it. (i am not saying IQ doesn't exist but it is much more nuanced compared to how some people talk about it)
Read intelligence by Stuart Richie. It's quick and dispels that intuitive notion of someone being good at one subset of cognition, must mean that they possess drawbacks in another.
Genetics to play a role into this. You mentioned Brahmans as their own race for a while, but after intermixing with low caste people, their IQ went down. This is why Northern Euros and East Asians tend to have higher IQs than others, because they mostly stayed together.
Brahmins are not their own race of people, they are part of the pajeet gradient. Yes, they have some group differences from others, but that's due to different selection pressures. The tiny bit of extra Steppe in them does not make them a different race.
And the Brahmins are fucking stupid as well, we can wait for polygenic scores to confirm if there IQ is indeed around 100. It seems to be just a couple points higher than the pajeet average. Their strategy would drop dead in the water with good ol discrimination and xenophobia.
Inherent group differences between populations is from sub-speciation differences and selection pressure differences. Most extreme example of a group with zero sub-speciation difference (Fst distance is very low, same ancient ancestral composition) and massive selection pressure differences are Ashkenazi Jews and south Italians.
Majority of intelligence differences come from being cold winter adapted alongside gene-culture-civilization evolution. The highest IQ you can get out of frozen hellholes is around 90 as demonstrated by Inuits who also have the biggest avg brain size. They have a small population, and never had civilization to explode their population. So they had no mutations for higher intelligence to stuff in that big brain of theirs.
Caucasians have been getting smarter every 1000 years on average ever since the civilization started courtesy of the neolithic anatolian farmers. Late antiquity and middle ages were eugenic for most Europeans and Ashkenazi Jews, it boosted our IQ to around 100 and theirs to the 110s.
North European's EEF ancestor's average IQ is in the low 90s. Western steppe herder ancestors were around the high 80s and low 90s.
It wasn't just the fact that we didn't race mix (we were in our own backyard unlike the Aryans in asia), we selected for higher intelligence, which will probably increase brain size as well.
Our level of intelligence can still change generation by generation. Right now it's very dysgenic, and if selection pressures keep up (regression to the mean won't save us), our bell curve will shift to the left which will fuck us over big time.
If you want cultural rebirths, reisnnance, and cool shit to be built. Then you might want to do cooperative eugenics with modern reproductive medicine. It's something we can do right now with fertility clinics by getting average families to incubate embryos made from donors on the far right side of the bell curve (ideally beauty, IQ/g and somethings height). Donors with g loaded occupations are great choices, especially if their parents have them as well. You'd have to comb through 100s of profiles to find the weirdow genius who despite being gifted, accelerated in school, but dropped out of college and decided to be a traveling hippy instead of a doctor.
