Well, there is the practical reality that I need to work, so that makes homeschool difficult at best. But I could make it work if I really wanted to. I don't want to though. For several reasons:
1. While I am well educated, I am not a good teacher. I have tried as a volunteer at several points in my life. I'm lousy at it. On the other hand, my DS goes to a school where all the teachers are really good.
2. I want my children to have more than my (or my and my DH) perspective on the world. If they only hear my voice, then how do they learn tolerance, evaluating different ideas etc. And how do I avoid passing on my ignorance or opinion on things that they should make up their own minds about? I have blind spots, like any other person, but I don't necessarily want to pass them on.
3. I have a limited amount of patience for my children. I am a great mother for about 6 hours a day. After that, I'm a witch. Who wants to learn from a witch?
4. I believe that kids need to learn from both adults and peers. I could be one, but its sort of impossible to be the other. School teachs not only reading and math, but also social relations and social behaviour. Yes, that could be learned in other ways, but why make life more difficult than it already is?
5. I could never provide the wide variety of learning tools that my DSs school has. Computers, sure. But science labs, music rooms, art studios, sports fields? Not possible. Ditto for number of teachers and their expertise.
6. Children need to learn to work with structures and groups. We can't always move to our own drummer in the wider world, sometimes we need to move with a group. School is a way to learn to do that more smoothly. Sometimes we have to wait for others to catch up, or move more quickly to keep up with others. Sometimes we have to do X when we want to do Y. Those are skills that should be learned early.
Now, I will confess that we chose a small private school for our children where they can get some of the individual attention, academic flexibility, and extra subjects that strike me as the positive points of home schooling, so we are trying to get "the best of both worlds".