Take the state out of the schools!!!!!

On the subject of education, I've heard that the US state school system is pretty crap. And i've also heard that this is because the teachers always teach to the level of the slowest members of the class. That just means that the smart minority get bored, frustrated and demotivated. Shouldn't the schools separate the smart kids from the less smart and really train them at the level that suits them best? Imagine a kid with 160IQ sitting in a class with an average of 100IQ. it just doesn't make sense! This is something that was realised in europe decades ago with great results, so why doesn't the US follow?