Hmm okay - I suppose my point is that the number of children who cannot be served by A levels/GCSE's is going to be very small - and like any child whose needs cannot be met in those ways you, as parents, have to expect a battle (usually because the provision doesn't exist - and probably isn't going to - I suppose the state could open a few boarding schools for the super bright, but many with children eligible wouldn't choose boarding). The law only has a responsibility to provide a 'suitable' education - not the best - obviously with money people might exercise their choice & choose to pay - if there's enough of a market someone will be providing something - even if you have to travel a long way.
In terms of typically bright kids (ds2 & ds3 are what I would call typical bright kids) then I do believe the state can provide for them. We're looking at secondaries for ds3 now. He's a child I could see at Oxford in the future - he has a very intense interest in one area (history) & obsessively reads around it - and likes historical holidays etc. Could he get to Oxford from the grammar? Yep - if he works hard enough. Could he get to Oxford from the local comp? Yep - if he works hard enough. Would there be a difference between the GCSE's he would take between the two? Not in terms of number, but at the grammar school he could take Latin, history AND ancient history if he wanted. At the comp he could only take history (we'd probably find some out of school Latin teaching for him if he went anywhere other than the grammar - no other schools offer it locally). Would he be held back by having different GCSE choices? No, I don't believe so.
Ds2, currently at the grammar (supposedly a superselective as it takes from miles and miles away - but not really because there isn't the population density to be super selective) will give up Latin & wouldn't go to Oxford in a million years (he's bright, but not what I'd call fiercely academic). Does the grammar serve his needs? Yep. Would the comp we put as second choice serve his needs? Yep.
The vast majority of bright children will be like ds2 & ds3 and their needs can be met, IMO, by local schools - probably the main issue being over subscription (not a huge problem at secondary in my area - so we do have a genuine choice of secondaries with a different feel/focus).
That doesn't mean children with significantly different needs don't exist - but they're rare - and then all you can do is do your best. Ds2 for example happens to be very talented in one particular area - we could have sent him to a school specialising in that - but he would have had to have boarded. We chose not to because we didn't particularly want him boarding (& couldn't really have afforded it - even if he'd won a scholarship - it would have been a stretch). So he goes to a good local school & is getting loads of experience outside school (& the good local school allows him time off to do that).
Any school has pros & cons - and as parents all we can do is weigh then up.
Incidentally - has anyone been following the progress is Wey ecadamy? That plans to offer a specific 'gifted' programme (and Latin - hoorah) - academically I liked the look of it - although the cons might outweigh the pros for me.