tbh many of the adults i know have no ability to judge which lines of questioning are fruitful or not specifically because they're so "on rails" or "adultlike".
for them a fruitful question is defined as something along the current trajectory. but they never ask if they're on the right trajectory because that wouldn't be something on the current trajectory.
Its not so much questioning everything that is childlike, instead that would be not knowing enough to avoid talking about it with people who don't know or care.
I don't think that's true. Think about the adjectives associated with curiosity and wonder - 'childlike' definitely comes to mind. 'Interest' is an adult word, though - that implies a trajectory and a path, where curiosity and wonder are general.
