Although people commonly complained about a growing "generation gap," the failings of school systems, the deterioration of values among youths, violence in schools, and so on, still many people came to believe that it was necessary and inherently appropriate that children be in this environment and exhibit these behaviors. Eventually, it came to be thought that school, in spite of its failings, was the one right place for children to grow up and become socialized. Any other environment was, by default, barren, empty, unhealthy, and sad.
Still, a few people felt in their gut that their children didn't belong there. And thus came homeschoolers.
Rachel Gathercole in The Well-Adjusted Child: The Social Benefits of Homeschooling