I often feel the same way. We live in a neighborhood with few kids, among my co- workers, there are no children who live close enough to make playgroups very practical. My problem with the word socialization is that it is ill defined and often used to shoot down the whole concept of homeschooling.
Social skills encompass a broad range of human activity.
I don't know many people who were unhappy because their scholarship hadn't been optimized to the last degree, but I do know people who felt isolated and alone, and have had their lives marred by those feelings of isolation. She has always preferred small gatherings to large ones and she takes her time to become accustomed to new situations. When we started homeschooling last fall, I was very concerned that she get enough social contact with her age-mates. We enrolled her in gymnastics, painting and music classes. We made play dates with her preschool buddies.