From experience there's a motivation, almost a compulsion, to follow the instructions to build the cool thing. Then... they sit there, those bricks never taken apart.

That compulsion doesn't seem present in freeform building, and there's been zero interest in it in our household. I know that's not true for all, but it seems like a lost art. Maybe it's because the IP sets show how but not the why it's constructed in a certain way, so given a bag of Lego most wouldn't know the process of creating something they can see in their minds eye within the constraints of the available bricks.