no, everything beyond functional skills is not easy for all students. But for some of them it is, and they need to keep learning maths beyond early secondary when they've got the basics of functional skills. It doesn't serve anyone to limit the regular maths provision to basic skills.
But also, there needs to be a basic qualification that struggling students can take to show that they do have functional skills. They might not be able to pass a GCSE for a whole variety of reasons (SEN, lack of ability, apathy, no parental support, etc), or they might be able to pass it if given additional years and teaching. But a functional skills paper (or a numeracy GCSE, or whatever you want to call it) is a good first step. It wouldn't stop those who wanted to carry on doing re-sits of GCSE the chance to do that. But it would stop the compulsory nature of resits that block access to further education. That's what is needed. Not a limiting of opportunity for those with the desire to do GCSE, but a possibility of another qualification for those who don't want endless resits.
Absolutely, it needs to be discussed and reviewed - that's what maths teachers have wanted for ages. Many would like a 2-GCSE plan, with one GCSE having basic skills, and another having further skills (and possibly a third having what is now in the further maths GCSE). Or a three-tier system, where students can choose 2 of the three tiers to enter, to increase their chances of achieving as high a grade as possible.
I don't know that it is completely incremental, as a matter of fact. I do think some children just 'get' maths, and for them, it is all relatively easy, and matter of extra teaching on some topics, and they will understand. Others, it is a real slog. They can get there, but it will never 'just make sense' in the way in does for some of us. They can learn to do it, and that's fine. But it's a qualitative difference at times. There are others who can get it, but the wording/format of the current GCSE doesn't work for them - a different numeracy test that is more straightforward might suit them better. There's nothing wrong with a functional skills type test - knowing what's on it, I'd be glad if many of my students could learn that material instead. They enjoy it more, as it seems more practical to them.
And again, nobody is labelling children as 'too stupid' by the age of 11. We are doing everythign possible to get those children through GCSE. I am a tutor, but work closely with classroom teachers. Nobody wants to write them off. We want to do everything we can to a) get them useful maths skills that they can use in their daily lives and b) get them through the GCSE to grade 4 or 5 or more. We try everything possible, we use all the teaching techniques we know. If you think there are fancy specialist ways of teaching this that we don't know, then for the last time, tell us what they are!! We don't care what the flight path for any student is (other than that is they don't live up to the expectation, the school will be penalised). We want them to succeed and get as high as possible, and to catch up if at all possible.
But if they don't, we want them to have the chance to do a decent qualification that will get them jobs. We want them to be able to go on to A levels or other further education, without being held back by an arbitrary government target that says they must have a specific exam grade on a specific exam. We want them to have the option to take the exam again, if they wish to, and just need extra years to do it. We are willing to help them do any of these things!
We would be happy for all sort of revisions of the current exam, and particularly the tiers and the content involved in those tiers. It's ridiculous that children should be spending time in classes where the work is beyond them and the exams are inaccessible. They should have the opportunity to study content that builds on what they know - even if it's below age-expectations - and to improve on that, and to take and exam that shows this.
You've clearly had bad experiences with schools and teachers, but it is by no means universal. Teachers truly do want as many children to success in maths (or English) as possible. We wouldn't have gone into this field otherwise.