Except that academic libraries exist for Academia and not for the public at large. The hoi polloi is usually allowed in but often can't borrow anything, especially in private schools. Besides, the collections aren't exactly appealing to youth -- how often when YOU were eight or ten did YOU read Shakespeare, or Kitteredge on Chaucer, or the Newton's "Principia," or Bohr's "Causality and Complementarity: Epistemological Lessons of Studies in Atomic Physics," or, as barefoot boy with cheeks of tan, settled down under the ol' apple tree to read Veblen's "Theory of the Leisure Class"?

But there's no reason why public and academic libraries CANNOT cooperate, or why there seems to be a "holier than thou" attitude among far too many academic librarians towards public librarians.