I don't think it's helpful to be that rigid about it. Both the teacher and the student has an interest in the student learning something. Sometimes we have to give each other a bit of leeway to get to the destination.

There's a whole "philosophy of education" discussion I'd like to avoid, but the goal of education isn't really to educate one person to their maximum potential, but rather to educate as many people as well as possible. The individual should sacrifice for the collective.

Trying to make it a straight forward linear dependency chain displays a sort of autistic adherence to rigid hierarchy that's really common in software people, but really uncommon everywhere else.