I have to say that I do have one child that, hard as I tried, could not be unschooled. If left to his own devices, his day would be filled with video games and television. When I forbade those, he would just sleep or lay around outside. NOt an ounce of motivation about even a hobby. Scary.
My other does very well with a more delight directed approach , thank goodness. At least I can enjoy it with one!