You must have a very limited view. You say you're worried about your nieces and nephews. Do their parents keep them chained to the kitchen table or locked in the house? Do they not join in any activities outside the home; what about church, Scouts, homeschool field trips, etc.? Do YOU ever offer to take them out anywhere, or get them involved in your activities?
We didn't homeschool our older two; I just wasn't ready for it. I liked the socialization of the PTA, etc, too much, I guess. When our younger two were in the 5th and 7th grades, respectively, we decided to take the plunge. We have never been happier. Yeah, I sometimes have to threaten bodily harm to get them to get their work done, but when the younger one went back to school for his first two years of high school, I STILL had to do that!
Our daughter graduated high school this year, after having homeschooled since the beginning of 8th grade. During her four years of high school she was a member of the Anime club at the local public high school, was in the Girl Scouts, in the Youth group at Church and in the Adult and Festival choirs at our Parish; and SHE'S the shyer of our two younger ones. She was accepted to, and received a very nice scholarship from a small Catholic university in FL and she's getting excited about leaving for it in a couple of weeks.
Our youngest son is very outgoing, but hated Scouts, and didn't even join a single after school club at this high school this past year. He has been enjoying chatting with folks on his online PC game, World of Warcraft. We'll be going back to homeschooling him starting this fall for his last two years of high school. He's looking forward to being able to take upper level Math and Physics at a Community college like his sister did. We're fixing to move back South this Fall, and he's looking forward to that too; not nervous about meeting new folks at all.
They all live at least a thousand miles away, alas. I try my best through birthday and Christmas presents.