"I would expect a child in secondary school with an IQ of 130 to be able to take a bit of initiative about their own learning"
A child in secondary school with an IQ of 130 may already have spent 7 years in primary having their ability and needs completely ignored. Do you think their initiative will have survived that 7 years? They are children, not robots, and even a resilient child has limits.
What about a kid with an IQ of 130 who also has ADHD, or aspergers, or dyslexia, or dsygraphia, or sensory processing disorder, or any number of other issues? Don't you think that perhaps they need support for both their ability and their area of difficulty, since otherwise the strengths and weaknesses will compensate and mask each other, making the child appear average.
What about a kid with an IQ of 130 who is in Kent or another 11+ area, who may have missed the 11+ cutoff by one mark for any number of reasons (twice exceptionality, slow processing speed, inability of parents to afford a tutor, recent bereavement, being sick the day of the exam etc. etc.) and therefore ends up in a secondary modern, in a class where there are no other kids of comparable ability, and teachers who are completely unused to dealing with that level of ability and have such low expectations that they may not recognise it.
"I would expect" fails to take account of any of these cases, and each such case is a situation where society and the school system has failed a child and caused suffering and long term harm.