From my perspective we already do what you are suggesting. It just done in less noticeable ways.  We have an almost no existing enforcement level of mandatory attendance for students; ask any  teacher.
We allow some parents an easy out by simply putting the child on a correspondence program where there is no way to hold that parents accountable if the child never completes a single assignment. 
We try changing things in schools by legislative and school board priorities that are so different from one district to another you would find it difficult to see them in the same state.
When given the option to review content in comparison to desired outcome we spend more time of faulting a common core of content than on how to implement the curriculum. 

At the same time we  have students who excel. Every year the military academies have Alaska students being accepted on the basis of academic achievement.  Our students attend and graduate from prestigious colleges and universities.