Schools are as much babysitting institutes as teaching ones. Kids are sent there to keep them out of trouble - and if they break out of this prison, "truancy officers" are sent to track them down. But teachers are not policemen, and it is hardly fair to expect them to play both roles at once. So it should come as no surprise that the quality of teaching can suffer as a result.
But what's the alternative, you ask? Well, homeschooling certainly provides a very different model. Although often dismissed as the province of religious cranks, I think homeschooling actually has a lot to offer. For one thing, it enables a higher quality of education. As Byron Harrison comments in the CT thread linked to above:
In our research centre we have perhaps 70 home school children in a research population of about 3000 children.
The overall impressions are that the Homer children are significantly more articulate in the presence of adults and, in a recent survey, actually outperformed their Normal-school children in 16 out 18 aspects of literacy. Interviewing those homers who have gone on to University showed that in the first year many of the Homers were shocked by the poor levels of general knowledge of the Normals.
Further, the social aspect of normal schools has little to recommend it - what with the bullying, the popularity contests, not to mention the horribly anti-intellectual, anti-learning culture which permeates them. Surely we could come up with better community institutes for the socialisation of our children - and indeed homeschoolers often do.
Two common objections against homeschooling are that it cannot provide the same exposure to diversity that public schools can, and that homeschooled children will lack social skills. (Though a public schooling doesn't seem to have helped me much in that respect, ha!) So I'll quote a couple more CT commenters who addressed these (mis)perceptions:
[M]y son and I walk everywhere and take the public bus (no car). He takes swimming at the Jewish community center (though we’re not Jewish), he regularly visits museums and libraries and galleries and such, and he's in Scouts. He also plays with the children on our street (who are a pretty diverse bunch!) without me anywhere in sight. We talk to strangers. We explore the city.
I suspect he gets far more "diversity" in his life than he ever would at his old public school!
Many people who encounter the home-schooled children of my acquaintance are surprised at their poise and confidence. These aspects are cultivated by the fact that most home-schooled children have a much wider range of contacts than do institutionally-schooled children. Home-schooled children do not merely sit around the kitchen table grinding through mail-order curricula (though some do). Instead, they are out in the world taking dance classes, art lessons, going to museums, the library. They are involved in projects they have chosen for themselves (and have the time to complete to their satisfaction).
As a result, instead of being segregated for up to eight hours a day with people the same age, they meet and interact with people of all ages. They are used to talking to adults, and do so, instead of staring diffidently at their toes.
Once one digs beneath the negative and misleading stereotypes, I actually find the homeschooling model much more appealing than the traditional one. By separating the educative and social aspects of traditional schools, alternative arrangements could, I think, do a better job of each.