The biggest un-addressed problem is sheer lack of will. A significant percentage of students will not do the work. They'll show up, they'll go thru motions, but will not do the actual work required. Telling them they'll fail won't help: they either don't care or don't comprehend. Punishments won't work because punishments are forbidden. Offering more assistance and resources won't help because those are tools, useless if unused. They do nothing, life goes on in an acceptable manner. They have no reason to do the work, so they will not do the work, and thus will fail.