Great comment! There are many countries which spends more than US like Switzerland so the only conclusion one can derive is that after some amount the marginal

Great comment! There are many countries which spends more than US like Switzerland so the only conclusion one can derive is that after some amount the marginal gains in quality of education are small. However the conclusion that marginal gains actually reduces are not correct. The fact is that quality of education depends on many more things after certain minimal spend is established. Teacher training and incentives, standards, methodology etc are much more important. For example, why are we still doing passive learning in classroom where students are expected to just sit and listen as opposed to hands on project based or Montessori style learning. Think about the difference just this will make. I also think US system is fundamentally flawed because of government established monopoly. This prevents other players to come in and make improvements. Even worse, students in US is tied to a school based on house a parent can afford. Why can't a parent take education allowance from government and go to any school they prefer? This would allow competition, private entities, market economy and most importantly fast evolution by innovating on other factors.