DD has an acquaintance who has some developmental challenges. This young lady is in a regular classroom (though she started school a year late) and works extremely hard for each and every grade. I often comment to DD that I'm impressed with that kind of dedication to learning. But if this young lady were left alone to follow her interests, with an attitude of "you'll learn it when you need to" I expect she may not have a successful future.
DD on the other hand has never really had to work. If I let her do whatever she was interested in she'd coast forever without learning how to apply herself. It's hard enough finding stuff that actually makes her work and is still developmentally appropriate.
CAN this methodology work for some kids? Sure. Public school works for some kids too. I however would rather err on the side of caution when it comes to my child's future (making sure they know what they need in order to make their way in the world).
This is not a zero sum game -- the choices aren't a) destroy my child's love of learning and crush their independent spirit or b) let them completely self education based solely on their own interests (and set their own bedtime too!). There's really a very large grey area here.
Extremism in education is part of what holds the PG kids back. The attitude that there's one right way (whether that way is common core or unschooling) that works for every child.
