There is a lot of truth to what you've said, but I think you may be confusing the functions with the spectrums. A percentage or scale representing extroversion on one end and introversion on the other is a spectrum, whereas the functions like Te, Ti, Se, Si, etc. are more concrete and just come in a specific order, as opposed to there being a large gray area like with the spectrums. When you look at it in terms of the extrovert/introvert spectrum, it's really difficult to say where I stand personally with those criteria, such as being energized by others. I have other things on my mind, like how to do the socially appropriate thing. I like being with people though, I think I've just been ridiculed to solitude for the most part, which has made me more used to being alone and working alone. Most introvert criteria doesn't fit me so well, and the introverts on here, most notably ISTJs, come off to me as being more socially apathetic than I am.