People equal friends and friends equal people. It is important for shy people to have people contact to make friends. Mothers need friends. Taking children with them helps mom grow friends. People equal friends.
Some people have more trouble getting out there than others.
Shy people or people who are true loners often seek safety by staying away from people. If they don't even work with many people, they will have a hard time sharing experiences with someone who is attractive to them and vice-versa. Elderly people or people who do not drive also have trouble getting out in most of the American world. Other people are isolated by physical disabilities, by geography, by abusive relationships, etc. New mothers are often too tired or just too busy to keep up an active and satisfying social life.