As somebody who was that "smart kid" I know that I personally felt that the easy-yet-time-consuming work was just boring. It wasn't until finding classes where I was adequately challenged that I began to care about the assignments, and it took years to develop the sort of persistence and drive that wasn't required of me in school.

Would I have been more successful at university and after graduating if I had more "grit?" I think so. But I didn't need it, so I didn't have it.

What can be done to prevent this? The obvious theoretical answer is to reduce class sizes, so that students can do coursework with other students who learn at a similar rate. If only America would adequately fund education...