Public schools all teach the curriculum you describe, the three R's, plus computer science plus whatever else they can afford. Students who come from homes that value education and learning learn fine in public schools, while others who don't value it, or value it less, do not. Every American high school teaches American history. If students don't know it coming out of high school, it is their fault, not the school's.
Many students think they can make a quick buck via sports or media, so why study? Wildly unrealistic but they don't know this till later, and the get-rich-quick-through -any-means-mentality in this country encourages this kind of "thinking."
The fact that you emphasize testing as a way of evaluating schools shows you know little about education, even if you are a substitute teacher. Emphasis on testing leads to rote memorization, certainly not critical thinking. You are probably unaware that nationally, charter schools perform about the same as public, or worse.