As an ex teacher, I don't think it's anything to do with class or even effort. It's to do with what is education for. Is it to give pupils a broad knowledge of where they come from, of where their society is and the reasons for it, of what is the most interesting in writing, music, art,science, etc? Is it about stretching their faculties and challenging them? Is it about preparing them for competing with life?
Or is it about giving them a sense of self worth, about being non-competitive, about smoothing out difference, about making sure everyone gets a reward?
Is it to get them through an exam or to make them curious and involved?
Is it about statistics and government targets or about getting the best out of each pupil?