The problem is that American cities are structured to keep the poor and minorities in nominally independent cities or suburbs that are geographically indistinguishable from the richer areas, but just independent enough to ensure that property taxes aren't shared.
It's also hard to escape the fact that many, if not most of these suburbs were explicitly set up to keep out blacks, latinos, Jews, and other undesirable groups. Until the sixties, houses in these communities often carried a restrictive covenant that explicitly prohibited sales to non-whites.
Canada shares a lot of the basic educational structure as the US, and sadly a good share of the racial baggage as well, but our cities are far more monolithic than most American cities. There are only two school districts in my city (pop. ~1 million) and students can register in any school throughout the district. The only choice I make as a taxpayer is which district, public or Catholic, I want my property taxes to fund.