I feel like the U.S. public school system was designed for SJ's, it's all about becoming successful through hard work.
It rewards hard work and consistency above curiosity and risk taking.Most of the kids in Honors classes, I've come to notice are SJ's, the valedictorian at my high school graduation was an ISTJ.
I think that's what gives most other types the short end of the stick when it comes to the school system, especially SP's and NTP's.
I also think the amount of rules placed upon students can be suffocating for P's most of all, as I think a large part of the fact that I am doing eons better now that I am in college than I ever did in high school is because they let me do my own thing, they don't try to hold my hand for everything or tell me when/where to be/ what I can or can't do, for the most part.
On the other hand all of the dumb, pointless, rules enforced upon me during high school stifled me and made me want to act out all the more.
To put it in short they treated me like an immature kid so I responded like one.
Anyway, not saying that rewarding hard work is bad thing at all or that SJ's don't deserve to be successful, but I think it kind of screws over the other types who may have different learning styles/ work ethics.