I don't think it's that complex. My personal premises are
* if the kid doesn't like to get up and go to school or is too tired over longer periods, the school is doing something wrong, not the kid. * if there are A LOT of kids like this, the school authority is doing something wrong (and so on, up to government) * an older kid needs support on every topic at any time when interest arises. It's the kids' choice not the schools'. * learning at school must be fun, at least 90% of the time.
That way whizzkids are easily detected, will be less frustrated and thus perform better.
I got some good example anecdotes but better won't "textwall" here :-)
Just imagine a world, where Einstein would get optimum support from young age so he would start professional physics years earlier.
Or one where he didn't go to the patent office but one where he worked in some factory or other place, not finding the spare time he needed to do physics.
Way too much luck involved if you ask me.