States were required to develop and implement "child find" systems. When word got out about the availability of a public education, some parents saw they had an alternative to the physicians' recommendations to institutionalize their children. As Val Bradley comments, this had a profound effect on the capacity of families to stay together.
If we mark progress in our field by those events that bolstered the ability of people with disabilities to remain and thrive in their communities, then the passage of the Education for All Handicapped Children's Act was probably the singularly most important piece of federal legislation. Working in family support over the years, I can't count the numbers of people I've met who were forced to place their family member in an institution because they couldn't bear up under the stress of caring for a son or daughter with disabilities for 24 hours a day – the result of the exclusion of children with disabilities from regular public school. (private communication)