Population density is what encourages :Fi:
In my opinion, introverted functions have a better understanding of phenomena than their extroverted counterparts.
:Ti: good understanding of nature / bad understanding of people
:Fi: bad understanding of nature / good understanding of people
:Fe: good understanding of emotions / bad understanding of business
:Te: bad understanding of emotions / good understanding of business
:Te: has a worse understanding of nature than :Ti:
:Fe: has a worse understanding of people than :Fi:
:Ti: has a worse understanding of business than :Te:
:Fi: has a worse understanding of emotions than :Fe:
In the past, people had to deal with lots of hard-to-explain natural phenomena. That's why :Ti: people were really useful. Besides, population density was low and their :Fe: duals had to create links with other tribes as quickly as possible. :Te:/:Fi: people were virtually useless and didn't reproduce much. Only the most attractive, perhaps.
Modern life involves living with thousands of people around. :Fi: people (unable to understand natural phenomena) became now useful, as they can understand people quickly. Besides, there is no need of understanding nature. In order to thrive, people have to think about making business (:Te:). That's how schizoid people (:Te:) became useful.
Today, :Ti: / :Fe: people represent a small % in the population, as having those ego functios won't probably help you thrive in highly populated cities.
:Ti: / :Fe: people work in groups. In the past, it paid off to cooperate with others.
:Te: / :Fi: people are individualists. It pays off to be selfish in the 21 st century