The purpose of (good) education is to focus the student's intelligence and energies into something productive that keeps on building i.e. 'knowledge' and hopefully critical thinking skills or igniting a previously unknown passion for X. It's supposed to draw the full potential out of children.
With children with needs outside the median, again whether it's 'strictly' an IQ thing or learning method thing, if you can't properly engage the child's interest or hold their attention, I agree, they will find other ways to satisfy their inclinations. Even if it's 'loafing about' or 'playing hooky' or being delinquent. True, 'seeking out stimulation' outside of what the school proper provides isn't always going to be so negative, but well, it kinda is.
That's not only unbeneficial to the child themselves but is also a distraction to other students and just overall not a good use of a school's resources.
This is what I mean by identifying and then meeting children's needs.
Also, while it's possible to attain intellectual greatness without traditional schooling, traditional institutions of learning and those set pathways are generally the way you have to go to gain access and publishing in certain realms. Like the sciences, including social sciences. I just see a lot of 'smart' people who never got a chance to enter academia or develop their intellect professionally, not because they didn't want to -- but because their school lacked the resources to meet them halfway. Or else they became slackers partly because they were never properly challenged and engaged in school. What a waste.