Having been to a bunch of different schools, selective, not, public and private, I honestly think the solution to this will be primarily technological. Allowing

Having been to a bunch of different schools, selective, not, public and private, I honestly think the solution to this will be primarily technological. Allowing kids to learn at their own pace with a solid kick towards an interactive textbook of some kind seems like a much better solution than segregation. Let teachers stick to what they're good at (supporting kids) and keep them away from the stuff they suck at (maths). And yeah, this will be biased towards the more self-motivated. But that seems fairer than a one-off arbitrary test determining a huge proportion of your future.