My experience is different. Growing up, I never heard of autism or the behavior pattern now described as autism. But I did see Thalidomide babies sometimes, and many cases of Mongolism and other forms of retardation. But as a parent over the past two decades, I have seen a half-dozen cases of autism just among families I know. The increase cannot be attributed to educrats' rent-seeking behavior alone. We may or may not have the last word on the cause, but there is a real phenomenon here.
As a science and business writer, I have seen many instances of government corrupting industries, including Big Pharma, by regulating them into distorted freaks. Think of the auto companies, electric-power monopolies, the old telephone monopolies, the housing market, the securities business, public education, green energy . . . I could go on. Pols and regulators circle the wagons to protect the monsters they have created, which donate to their campaigns. Corruption festers where the competitive market is kept out, and politicians make deals for their friends.
Over the past 30 years, government, Big Pharma, and the Big Bland Media have pushed certain experimental studies and suppressed others (concerning cholesterol and fat, to take a different example) for reasons irrelevant to the truth, just because political involvement in medical matters has become so huge. Until the situation changes, we are obliged to be skeptical consumers of both government and its medicine.
When I was growing up, retarded and mentally ill children were often placed in institutions for care. There is more of a push to keep these children in their families these days. If most of the genuine autistic children were institutionalized in the 60s, but the institutionalization rate has been dropping, of course you will run into more autistic children.
There is also a simple phenomenon whereby you begin noticing something only when your attention is drawn to it. Furthermore, with the use of prenatal testing, about 90% of the children having a developmental disorder with a known genetic basis (e.g. trisomy 21, 18, or 13) are aborted. So there just aren't as many children with developmental disorders these days, making the remaining ones stand out.
My point, said in a rather roundabout way, is that there are all kinds of reasons for increased perception of autism that don't equate to increased incidence of autism.