You know you have actually answered the question, right?

Yes, children are weak, esp. if their parents play the authority/obedience card rather than preparing them for the journey, and monkeys are weak too, maybe not in the jungle, but definitely in such a controlled environment.
Breaking out wouldn't even cross their minds, something else has to happen first, and that what you wrote, that is it!
The realization you mentioned is the first step.

In a social environment, communication with others, the spreading of an idea, is the next step (otherwise the social environment has the same effect as the icy water).
And once the monkeys get that banana, either together or by at least allowing the "daring one" to try his/her luck, only then it is time for the next step.

Thank you for answering, Chris!