How do others feel about academic success, and the motivation of/for it?
I think academic success has different meanings. One can look for success, I mean being in a competition to have a good ranking. One can look for a goal to reach in a career plan. I think INTj are more interested in achieving a goal than getting some success as a part of a competition.

One my side, I've had lots of trouble at school, college and university when the exams were more a question of memorizing a lesson than a question of resolving a problem. So I've been a little more than average student with some problems of "short term motivation for some lessons" but I had a very long-term plan and despite these short term problems, my tenacity helped a lot in achieving my goals, and I ended up with a PhD. The road was long but I've made it.