I suspect the truth is that most types have a heathy disinterest in over analysing themselves lol. The reason there's so much psychoblather about INFJs is that we wallow in it, so the web sites get loads of attention, and that draws in some other types as well out of curiosity - it's like going to the zoo maybe
. I guess the apparent scarcity of INFJs is another factor - whether the figures are accurate I don't know, but only once or twice in my life have I met a real life INFJ person, and I'm 70. It's a rather special experience coming onto a forum like this and finding that there are others with a similar way of relating to the world. In most social settings, we are having to work hard to fit in, while the others there are in their native element.
Very much agree. A lot of the guys I met working for the British Antarctic Survey were ISTPs and they were really good, easy company, gifted practically and extremely adaptable to unexpected situations.