One thing that I've found, over the years, and that's a lot of so called "brilliant" students at school can't handle university. They invariably dropout in the first semester or at the end of their first year. The problem is they're so used to having someone look over their shoulder (i.e. the teacher) that they can't handle having to be responsible for their own education. Many of them have not been taught to research properly, nor have they been given the right tools to handle the responsibility of having to do things by themselves. Some manage to pick this up going through their education, but not all of them that do so are the ones with TER/HSC/OP scores of the highest value attainable. Even so, those that can and do manage university don't find it a cakewalk. All, accept those rare cases where the person has eidetic memory (and I knew one, personally...grrrrr
).