A civilised, modern society must act to ensure that a high quality education is available to all its citizens.
Universal education is obviously desirable from a humanitarian point of view.
However, it can also be justified on purely pragmatic grounds. However, they are also contribute to society in ways which, though not directly measurable, are often equally salient, if not moreso. For example, scientists and technologists contribute innovations and inventions, either of a practical or a conceptual nature. These innovations don't necessarily have to be patentable techniques or technology. Intellectuals and writers make valuable contributions to the cultural and intellectual sphere, helping the society to better understand itself.