My wife and I discussed this issue last night.
Social media has taken away the basics of communication (face to face that is) from many. The ability to go into a popular restaurant bar, and strike up a conversation with a total stranger is lost on many nowadays.
It is those skills to connect to people that makes them feel lonely. They only know how to type a tweet/text/post.
Note: It is not lost on me that I am here, on this forum.