Yes, shoring up marriage will help the middle class; shoring up education will help it even more. Having less education correlates with every social ill, from going to prison, to not being married.
Schools need to make the development of a love of reading an absolute priority. Avid readers read better, write better, concentrate better, and do better in all of their subjects, across the board.
Schools are now making the teaching of skills their priority. Policy makers seem to have no idea how children really learn. Flood the classrooms with books; let children have choice n their reading material. Skills will take care of themselves, and the middle class will thrive.