Think about how the outcome of the Greco-Persian wars was influenced by the fact that the army of the Hellenes consisted of citizens of the Greek city-states, and the army of the Persians consisted of conquered tribes and peoples. What were they fighting for?
The citizens of the Greek city-states fought for their independence, and the Persian army had no common goals and interests with the Persians. This led to the cohesion of the Hellenic army and the weakness of the Persian army.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.