I don't think schools are likely to do a much better job of socializing their students than the various mechanisms in place before compulsory schooling; they probably do do a better job of conditioning students to accept a certain type of authority figure, but that's an argument that doesn't have any place in a business plan.

Those aren't the alternative here, though. The alternative is homeschooling or whatever improvement on contemporary homeschooling we can produce. And having known a few homeschooled kids in my time, I'd have to say that no, they aren't socialized as well on average as conventionally educated students. I'd speculate that this is due mainly to missing out on a large set of potential social contacts -- many themselves poorly socialized, of course, but also including quite a few adults involved with the school system or with schoolfriends. That's all anecdotal, but I don't think I've ever seen a controlled study and am not sure how you'd design one.