In a thread filled with anecdotes, and people who consider themselves experts on school because they went to one, the idea that you criticize is just about the only one with basis in research. Teaching the material is an effective way to gain insight on a subject.
> We don't gain anything by throttling the motivation of gifted kids
This keeps surfacing every time someone brings up education. Probably because it is so easy to argue against. The thing is, nobody wants to do that. The question at hand here is what makes for a better education for gifted children. That's not as clear cut as one might think.
For a given pair of students X and Y, it may be a poor investment for X to teach Y anything, if X will almost surely dominate Y within the problem domain. It would be stupid to force X to teach Y in this setting.
We need smart people in society so that we can advance. They are the leaders that will help move the needle. If we burden our best and brightest young people with "educating" their peers then we as a society lose out. The gifted children should be free to learn at their own pace so that as they get older they have developed expertise that the regular people will never achieve.
This isn't communist Russia. We don't gain anything by throttling the motivation of gifted kids except making the regular kids feel better about themselves.