Not one of them had at any time been subjected to sojourn in a state hospital or institution for the feebleminded. This seems to be significant in view of our experience that such an eventuality has invariably cut short any prospect for improvement (Kanner, 1965).(source)
If you read the histories of the autistic individuals seen by Kanner, it is clear that this consistent lack of intitutionalization in the good-outcome group cannot be explained by "less severity" or anything of the sort. Most of the rest seem to have been institutionalized, judging by Kanner's original 1943 paper and its 1971 follow-up.
I'll leave that as food for thought for those who supposedly advocate for good outcomes in autism, at the same time that they promote the notion that autistics naturally belong in institutions.