They were not in your classes. They’ve always been around.
And what about the severe autistics that still wear diapers at 12, have never spoken a word or made eye contact?
Remember classes with them?
You are correct.
I know a family where one of their several children was institutionalized after mental health workers said that the child would possibly be a bad influence on the siblings.
The child was about ten years old at the time the (appx 1965). Once in an institution the child picked up behaviors from the other residents as autistic children tend to do, thus complicating a diagnosis and bringing about a pharmaceutical attempt at a cure. When the movement away from large institutions came about there was an opportunity to treat the (now adult) person outside of the influences of an institution and it was determined that the only appropriate diagnosis was autism. The person is doing well in a group home setting now and works at a paying job.
My point in telling this is that even though autism was discovered earlier, there was not a quick acceptance of the condition and certainly no uniformity in treatments. Many children were routinely sent to institutions and were not part of the student body. They weren't included because it was thought that their condition might rub off on the 'regular' kids.