I see your point. But segregation can also occur by entire schools. In CA (where I live), budget constrains and therefore class sizes makes it very difficult for public schools to cater to the individual needs of students. For this reason, our son is going to a private school (partly an economic decision for us - the cost of a house in a town with great public schools was $500,000-$600,000 greater than the house we actually purchased).
We checked out many public and private schools to find the best fit for him. Given the kinds of math he was doing before entering Kindergarten and his inquisitive nature, we could see that he would be bored and not challenged going through any of the public schools we checked out. His private school does a great job of exactly what you say - different flavors, different emphasis, different difficultly in homework among essentially same-subject classes.
We checked out many public and private schools to find the best fit for him. Given the kinds of math he was doing before entering Kindergarten and his inquisitive nature, we could see that he would be bored and not challenged going through any of the public schools we checked out. His private school does a great job of exactly what you say - different flavors, different emphasis, different difficultly in homework among essentially same-subject classes.