A lot of American school districts depend on property tax values for funding. You get natural class-based school segregation as a result.

>A bit of refinement on that thought. In America, inner-city schools are mixed bag. If you live in someplace like Cambridge, schools tend to be good. Boston is a mixed bag. Same is true for other adjacent cities. However if you go to places like Westford, Newton, Wellesley which are very high earner high value properties, the schools tend to be consistently very good. Then you start moving into more rural places in Massachusetts like Pepperell, Townsend, Athol and again the schools are more like inner-city schools, underfunded and not very good quality.

How much of that is the quality of the schools and how much of that is just richer parents who can/will pick up the slack in the event that the school system doesn't do the job as well as they want it done?

If stats on median and per capita income are to be believed then the kid from Wellsley has a huge leg up on the kid from Athol even if you assume they get the same education.

For better or worse the quality of public schools depends far more on crime rates and income levels of the surrounding community than on school funding levels. There's very little that schools can do to to help pupils who are growing up in a difficult environment. By all means let's fund schools appropriately, but that's only going to make a marginal difference in outcomes.