This is quite a tangent... But how are you sure about this? I have known many high performing kids that felt severely under-challenged in secondary school, or were even picked on for showing genuine interest in their material. Some of them made it through and turned out fine in the end, but some of them didn't. Some ended up dropping out early, or severely under-performing their potential and throwing away a shot at becoming "grad school capable". (Whether on purpose, due to self sabotage or boredom, peer pressure, or bad habits). The teachers did their best but had to focus on the even more at-risk students.

Not all high-performing students will do well regardless of their environment. Some will crash and burn without support, and that doesn't only mean "accelerating them farther faster". It can be enough to group them together with other kids that are similarly enthusiastic and curious, so that they don't shoot each other down.