I suspect that in that era, when I was also at primary school, several factors applied to give the impression that things "weren't that bad".
Primarily, there were "special schools" where the most challenging were educated. Additionally there were fewer dual income households, and wider family tended to be "the village" that helped raise a child who might not make it into education or qualify for institutionalisation.
Those with challenges such as autism that did get into mainstream education were also subject to very different parenting and teaching styles than are considered best practise today. They learned by fear and the slipper or cane to conform. Bullying would also have been commonplace.
At secondary level kids who weren't performing educationally could be sidelined with little oversight. There wasn't the emphasis on staying in education and getting good grades and going to Uni that there is now. There was the option of leaving at 16 and going to work, which for some probably gave them the lifeline they needed to get out of the rigid education system of the time.
The argument that autism has increased, and remember it's a spectrum, can't be definitively quantified because it was always there, in the form of the odd kid, the eccentric family, etc.
We now live in a world where paradoxically diversity is championed, yet also seen as a problem to be solved, because the latter feeds the capitalist machine. Which is no doubt at the root of Trumps ramblings yesterday, plus the massaging of his saviour complex ego.
We're conditioned to live in a world that moves fast in every direction, with simple solutions to complex issues, some of which don't need to be issues at all if approached with a bit of common sense and compassion.
What Teump has done is incredibly dangerous and regressive and could well lead to maternal deaths, autistic children being used as guinea pigs and traumatised if new "treatments" don't work for them, and tried and tested vaccine programmes being dismantled causing increases in diseases that have been largely controlled for decades. Not to mention the incredibly unfair and unnecessary psychological torment of making women feel responsible for their children's issues without any definitive evidence that they are.
I'm absolutely disgusted and raging at the whole thing and the day can't come soo enough when Trump is ousted from office one way or another.