You seem to be misunderstanding. You seem to be implying that masses of children will go without education if education becomes voluntary. I don't believe so.
The thing is, I can remember being a child pretty well and don't have a particularly idealistic view of childhood and children. I don't think that most children would go to school, or bother to turn up at lessons, if compulsion was removed. Not enough, anyway.
Most parents have neither the time nor the money to educate their children at home. Furthermore, the tragic reality is that the culture of "self-education" has declined along with all other communal and mutual activities in the horrific onslaught of consumerism and mass culture. It would not magically return just because it suddenly became urgently needed; things don't work like that.
Not quite sure what you're arguing here; is it that manual labour is on the way out (a laughable suggestion, frankly) or the education system acts as though it must be and fails to properly educate children likely to go into manual jobs (a position that I would agree with, actually) or something else?
I don't give a damn about "the market" (strictly speaking I don't even believe in "it"). What matters to me is that children lean how to read and write, learn about the World that they live in, learn what they need to to become good citizens and learn what they need to to get a decent job at the end of it (or go onto university or whatever) so that they can provide for themselves and their families. I will admit that this sometimes seems almost as utopian as what you're advocating, a fact that is just a little depressing.
My free will as expressed at the age of five should not be holding me back at the age of fifty.
This may be true (in certain cases it certainly is). But it's not nearly as much a waste as having large numbers of people unable to read a book and unable to write their own names.