The rise of specialists and the demise of generalists

People long have noticed that the universal genius of the type of Leonardo da Vinci has increasingly become rare. The Think-Tank Ideaticon has published a blog post “The death of the generalist in the age of hyper.specialisation”. The title really says it all. What all of us intuitively know. The world is ruled by specialists and generalists are far and few.
The reason is pretty obvious: if a generalist and a specialist apply for a job, a university scholarship, a position etc., it will most certainly go to the specialist. Jobs, university majors, etc. have become extremely domain-specific (even though that contradicts the very etymology of the word “university”. There is no such thing as a vacancy for a generalist. There are lots of people out there who have vast knowledge and a variety of skills, but find it hard to get a job.
Where do generalists and specialists come from, evolutionarily speaking? Why do some people have the propensity to become specialists, whereas others tend to become generalists? I would argue before the advent of farming all humans were generalists. There was almost no specialisation, with the exception of the division of labour between a more male-specific domain (hunting) and a more female one (gathering). These were never absolute specialisations, though, as even women could hunt alongside men. Not even child-rearing was an exclusively female domain. Hunter-gatherers practise alloparenting. I.e. a lot of people take part in parenting (it takes a village to raise a child). In fact, the title of the “Best Dads in the World” has gone to the Aka hunter-gatherers in Africa.
Specialists arose with the advent of farming. Very likely with a change to our serotonin system, which made it possible for early farmers to continue work even when it would have started to become tedious for hunter-gatherers. Soon after the advent of agriculture public life started to become specialised: farmers, smiths, fishmongers, etc. Nowadays we haven’t only got psychologists or even cognitive psychologists, but cognitive neuropsychologists.
However, not all people alive have inherited their genes from early farmers including high serotonin levels. Generalists still do exist, but they most often do not hold leading positions. A look at the income distribution and personality type makes it clear which personality dimension goes with specialisation:
While extraverts find it easier to “survive” in a business world that is just crazy for introverts, it is really the J/P dimension (or conscientiousness in the Big 5 inventory), that separates specialists and generalists. I have argued before that J-types are conscientious learners (they have fewer interests but pursue those with more depth), whereas P types get bored more easily and want to move on to new knowledge more quickly.  The following diagram illustrates the point that both types learn about the same amount in a given time, but with a different distribution.
What is increasingly happening already at the school level, is that generalists get filtered out by the system. When students can prepare for tests, J types will always have the advantage.
P-types are therefore much more likely to get the feedback that they are “bad at” a subject and come to dislike it. There are other factors that contribute to the relative “unsuccess” of  P types: they are more spontaneous and plan less than J types. This might get them more easily in trouble at school at work, when missing deadlines, etc.
Most of the world’s top specialists are INTJ (Newton)/ENTJ (Carl Sagan) types, whereas most generalists would be INTP (Einstein)/ENTP (Leonardo da Vinci). This difference can be illustrated with the example of Google and Facebook. The Google founders Larry Page and Sergey Brin are both INTPs and this is reflected in the company’s DNA: Google has such as a wide variety of products (from search to healthcare) that is is hard to enumerate them all This is so uncommon in business that a lot of people, including Steve Jobs, have criticized Google’s apparent lack of focus. Facebook, on the other hand, clearly carries Mark Zuckerberg's INTJ personality. The company is so focussed on social media and messengers (Instagram, WhatsApp), that it practically owns the domain.
In evolutionary theory, specialists arise when the environment is relatively stable and generalists when it is relatively unstable. In unsettled times like ours, we are all aware that the world needs more generalists, despite all the great specialists we have got, to solve the increasingly complex problems we are facing. Governments and businesses should be working on that problem. The Google founders went to Montessori schools and Google and they created a company that should work well for genius generalists like them:  reduction of hierarchical structures, plenty of flexibility, 20% time and possibilities to relax and zone out. This should be a hint for those you prefer things the traditional way.