Suburbanization and television can both be said to have begun a process by which American culture has become more atomized and individualized. Both of these factors made it easier for Americans to have much less interaction with other people over the course of a day.
When Americans lived in cities and did not have television, they interacted with neighbors a great deal. They lived very near to other people. They did not have as many forms of entertainment that could be done inside their own homes. Therefore, they spent more time doing things with other people outside of their own households.
This changed with suburbanization and television. Neighbors were at least somewhat farther away and there were fewer of them than would have been the case in a neighborhood of apartment buildings. A man would drive his car home from work, park in the driveway or garage, and come straight into the house. This made for less of a chance to interact with others. Once inside the home, the family could simply watch television all evening long, making it unnecessary to interact with other people.
These factors helped to make American society less communal and cohesive than it had once been.