'The Knowledge' and lesser other knowledges and schooling

In order to win the argument about the validity of exams and the exam curriculum, the people who run education have to impose a non-contestable, a mustn't-be-contested notion of 'what is knowledge'. It just is. The knowledge that has to be studied will be and must be the knowledge that is. The only knowledge. The knowledge. Or just 'Knowledge'. 

All other knowledges or abilities or capabilities outside of this 'Knowledge' have to be treated as lesser, or irrelevant or not important or not-knowledge. 

Part of this process, is also the idea that the best time (or indeed the urgent and only time) this 'Knowledge' can be acquired is between the ages of 4 and 21. Any knowledges outside of this time frame are also lesser. 

Support for the acquisition of 'Knowledge' or other knowledges outside of that time frame also have to be less important because supporting it would kick away some of the control and containment that you can get with a test-crazy regime imposed on young people.