My HS Algebra teacher was a drunk that sipped 'coffee' all morning, and mostly slept through his classes before 10am. It took my algebra II teacher (who was a whiz) to make up for all the lost time.
My point is that there's no guarantee in the school systems, either.
It quite likely that some of the plagues that haunt public school is present in American society at large. It shouldn't surprise us that homeschooling is beset with imperfection and is not a cure-all. The idea of being able to perfect education is a myth and a serious misunderstanding of human nature.