It doesn't, actually. It implies that when a school district's funding is determined by its property taxes, the wealthy will congregate in wealthy school districts while the poor will be marginalized into impoverished ones. Further, that pursuit of decent education becomes transformed into the pursuit of pricy real estate which further drives the stratification of education and society. I'm not going to go toe-to-toe on four links that refute an argument I didn't make. I linked to a book; you wanna attack "me", read the book.The idea has an implied association that there is a very good correlation between money spent on education and outcomes.
That makes more sense I guess I would have to go read the book to see what data she uses to support that argument. I always assumed wealthy people congregated in the same area even if that wasn't the case due to the safety, prestige and networking aspect but I could be wrong.