Wonderful question. Since this is tagged as "Farenheit 451", we can look at it through today's lens as well as Bradbury's. Writers who deal in the future often looking at something they saw in minutia or on a small scale in their own time.
Are we lonely because we haven't real conversation in our society? Real is the key word. Our society often communicates in text messages and emails in which the writer may have put thought, but not writing into its content. Therefore, the message may be lost. Even face to face conversation often loses meaning due to lack of effort. The result of this can certainly be loneliness and feelings of isolation.
What people choose to do with mass media determines the extent it controls our lives. For instance, I hate visiting with one set of relatives because the TV dominates the visit. I have never seen their television in the off position and their watching it continues the entire visit. Therefore, they are to a very real extent isolating themselves from the very people around them.