Except presumably, the reason you don't claim to be good at memorizing license plates or learning the hard sciences is because you actually don't have those skills, and not because you are concerned that having those skills would be seen as moving in on someone else's functional turf. But I (and many many others) actually are capable of making quick connections between unrelated disciplines in exactly the same way you describe: take your example about relating ways of life in the past to ways of life in the present (or even extrapolating those principles to the future). I don't get what the big mystery about that skill is - it's just a matter of drawing parallels and identifying universal principles. If that's all intuition is, then I can promise you, intuits comprise well over a few percent of the population.
I strongly disagree. SJs, because of Si, have completely different strengths, on the whole, than NFs. Same with NTs. It's not just about having certain hobbies or skills. The ability to almost instantaneously perceive underlying principals and realities is not something that most people do, or even care to do. I'm around people every day - listening to them talk, reading my peers papers in English classes, and interacting with people on the Internet - and I'm telling you that Ns do, in fact, make up a much smaller segment of the population.
I think this is what confuses people who take the Myers Briggs test. The basic test asks questions about concept vs. detail; theory vs. fact; associative thinking vs. linear thinking, etc... I spent years thinking I was an N because of those questions and wondering why I couldn't relate to either the NF or NT temperament descriptions: I'm not good with hard sciences, I don't always fall back on 'the rational,' I'm not creative in the least, and I can't empathize all that well.
Why did you think you were an N?
The cognitive functions tests were a bit more clear to me because Ni and Ne seemed to require something else - something subconscious or (in the case of Ni) almost supernatural. I knew for a fact I didn't "pull answers out of an invisible stream of ideas" or "use a totem or other symbolic focal device to spot unseen trends." (probably got those way wrong... trying to write them from memory).
My problem is not in the least with Ne (or Ni) as a function, but only the description of them. You can't have it both ways: intuition can't be something as simple as making connections or drawing parallels and at the same time be seen as so rare in the population. If it's having a legitimate "aha!" moment where the subconscious creates something where nothing existed before - yeah, that's an unusual ability. If it's being able to understand a theory or make comparisons between disciplines, that's not such an unusual gift and that definition has probably led a lot of Sensors to misidentify on that basis.
What you describe as "aha!" is Ni. Ne is the ability to see underlying patterns in everything on a subconscious level (which is probably why it is so difficult for Ns to effectively describe this process outside of its results), and analyze them, and I know from my own personal experience that it's a rare ability in the general population. It's not that the general population can't see them, it's just something that takes more effort on their part, something that doesn't come naturally and quickly to them.
I have a little Si, and if you are an ISTJ you have a little Ne. Everyone uses a variety of functions, but what makes you a particular type is your primary preferences and strongest ability.
I have no idea why some Ss mistype as Ns. I have a friend, for example, who totally mistyped herself as an ENFJ when she is obviously an ESFJ and has even told me herself that she prefers subjects which are factual, hands-on, and related to her daily life. I think it's because both are Fe dom, plus she believes she has latent psychic abilities, or "women's intuition" if you will, and that's how Ni - the auxillary function of ENFJ - is described to some degree.
