I think SEN/ND issues are more visible in many ways.
Yes institutions in the old fashioned sense hopefully went out with the ark, but there were still a lot more special school places in the 80s/90s compared to population number, it was also easier/more common to exclude pupils from mainstream schools. And some children with milder support needs were able to be accommodated in mainstream classes on a reduced timetable and/or with TA support, which I understand is more difficult today partially because there are more children in MS school classes with needs, but also there are fewer TAs, the teachers are more stressed out with more expectations on them so they can be less flexible, class sizes are larger, and a compound effect of having serious behaviour issues in classrooms (because of more intense needs and/or children less able to cope) is that there will always be some children in the class who either copy that behaviour, or are unsettled by the general chaos who would cope much better if the class was calmer and more predictable - they in turn might today be identified as having SEN/SEMH whereas they might not have been picked up on in previous decades/generations.
It is also (rightly) no longer acceptable to write children off as stupid - I expect there were children in classes years ago who weren't engaging or learning but as long as they learnt to keep their head down (which they might have done either because it suited them, or because they believed the "stupid" label, or due to fear of harsher discipline) then they went under the radar with a lot of teachers not bothering with them. Whereas today teachers are expected to put in the effort to engage those pupils and "get results", while not being given any extra resources, time, training which is actually helpful etc. And barely any flexibility or room in the curriculum to accommodate pupils who might not learn in an exam-focused, sit down and study, academic type way.
While including and engaging these pupils is important, nobody seems to acknowledge that this is a MASSIVE amount of extra work which was sort of unofficially never expected of teachers before, and nobody wants to talk about the fact that people are so varied that education cannot possibly be one size fits all and it never has "fitted" all, anyway. I don't think the old way was right, but I also don't think you can just shoehorn proper support for these kinds of SEN/SEMH pupils into a teacher's already complicated job within the current school system. This is just more invisible labour expected of a majority female profession.
It feels more visible online because you have people talking about SEN/ND issues both on social media, parenting forums, and in news media, on TV, online newspapers/articles etc. It's everywhere and it's become this huge topic of discussion which makes it feel more prevalent than it is - people say "everyone has autism now!" etc when really it is almost definitely still a minority that they are talking about, even if it is a large minority. And there is "official" discussion about SEND budgets because costs associated with SEND are increasing all over the country, and nobody seems to know or agree what the driver for increasing costs is, which is why there is this debate about whether or not the increase/costs are legitimate, and lots of avoiding the elephant in the room which is that no politician will outright admit that they were perfectly fine with the old way of cutting costs which included not bothering to educate disabled children, beating children into submission and not bothering with children who find it difficult to engage with education.
Similar to writing kids off as stupid in the past, I think there was less bother to chase up persistent absentees or notice patterns of truancy etc, and lower standards in terms of qualifications when you left school. There are a lot more records now so everything is more accountable. People in my parents' generation left school without any qualifications sometimes, it's not an uncommon story at all. I understand that the labour market in the 60s/70s/80s was also different and you could get jobs much more informally. My grandparent's generation (who left school during wartime) were full of stories like "They asked me if I wanted to be a nurse or a teacher and I thought neither, so I went and signed up for the Land Army" or "There was a factory in the town so I went and got my first job there" as though you just walk in and get offered a job, which sounds almost inconceivable to 2020s me, except that I now live in a German village where life is in many ways still very much like this - everything is very small scale and local, and if you get involved in any aspect of local village life, you meet people and everyone knows everyone else including the foreman of the local factory, so you are really never more than a couple of steps away of knowing where things like local vacancies are.
But the world doesn't work like that any more, and it is more difficult for people who struggle at school to get a job without qualifications, you even need patience and computer skills just to apply to things like shelf stacking in a supermarket because the application processes are all online.
I think a lot of undiagnosed ND people in the past (and present day adults) also end up with mental health struggles or addiction problems or in the criminal justice system - the estimates of ADHD and autism rates in prisons for example are shocking. But people with those kinds of issues are invisible to a lot of people. Or they often tend to live quite alternative lives off the beaten track, being attracted to subculture or simply keeping to themselves, being quite isolated (which may suit them, if they are introverted). So again, not very visible to the majority, although this is getting well away from children in schools/EYFS.
I do think early intervention or lack of is key because it is known to make such a huge difference in a lot of cases, which is why in the US they are really hot on it and almost intervene a bit TOO much and some people argue that it's unhelpful and causes anxiety in parents and a lot of the time children will catch up on their own or don't need to be pushed into a box. There are always going to be children who are developing slower than average and who may benefit from intervention but will catch up, more or less, on their own, intervention or not - and there are always going to be children who will benefit from early intervention but will always have complex needs no matter how much intervention they have, and it's the group in the middle, where I think that a lack of intervention/understanding can often place them in a sort of "no man's land" where they're not actually in the complex needs group but they certainly have much more complex needs than can easily be met by mainstream settings, and then you get a kind of snowball effect, which I think we are in now, where the cycle goes like this:
> Service (intervention/assessment/support) can't meet demand because budgets have been cut and/or demand has increased (budgets HAVE been cut everywhere, so this is not only down to increased demand).
> Service increases waiting time and/or prioritises the highest need cases
> Children with a moderate or mild need get older and still have the same struggles and/or fall further behind, and are stuck in mainstream without support, which can't cope with them.
> Children in this extremely stressful situation develop secondary issues because of this stress e.g. a lack of social skills or a communication problem makes it difficult for them to have positive interactions with peers and adults, their repeated experience of negative interactions cause them to feel anxious about social situations, avoid those situations (perhaps, if you like, through excessive screen time - you can also substitute motor skills in place of social if you like) and therefore have less opportunity to practice the skills they need, they fall back on less-positive approaches e.g. lashing out physically out of fear/anxiety because they do not understand the behaviour of other children, which makes the classroom unsafe for others and may result in behaviour management that the child (if they don't understand or don't know how else to resolve a problem) may experience as unfair, confusing, or at worst, traumatic. It does not change the behaviour because the underlying issue was not solved. Adults feel frustrated with the child and the child comes to see adults as untrustworthy or themselves as bad. This can happen even when everyone involved has positive caring intentions.
> By the time the child gets to the end of the waiting list their problems are severe and the secondary issues such as behavioural problems or depression/anxiety or school avoidance are a huge barrier to them actually engaging in something which would help and so they appear to have much more intense needs than they may have had if they could have accessed intervention at an earlier point. It is also harder to catch them up on the skills they are lacking because they are now further behind. Bear in mind they don't necessarily need to catch up to where "everyone else" is but even to the level that they can engage with school/peers/etc.
> Also, because the child's needs are more intense and therefore complex, this increases demand on the already overwhelmed service, which takes us back to the start again.