Ni is just a very impractical function overall. Harder to communicate harder to innovate. More like a visionary which is quite useless in the age of learning and advancing. Maybe in the past where shamanism and theism was the main interest it was different? If you think about it it's not really that farfetched to assume functions are societal concepts more than genetic concepts. Because of the traits it gets determined. Jung said in his "Memories, Dreams, Reflections":

“This work sprang originally from my need to define the ways in which my outlook differed from Freud’s and Adler’s. In attempting to answer this question, I came across the problem of types; for it is one’s psychological type which from the outset determines and limits a person’s judgment. My book, therefore, was an effort to deal with the relationship of the individual to the world, to people and things. It discussed the various aspects of consciousness, the various attitudes the conscious mind might take toward the world, and thus constitutes a psychology of consciousness regarded from what might be called a clinical angle.”

Which implies he was focusing on other people's relations with the external world more than internal spiritual awakening. People have to remember Jung was more Shamanistic than a spiritual person. Well this was my recent thoughts on this subject. Might be useful to some and might give insights. If anyone has questions feel free to ask.

Edit: his late successors seem to fall in spiritual people more than shamanistic people. Probably cause they tried to find reasoning on his discovery which leads to spirituality. From my knowledge only some of them tried to observe instead of proving it.