If the function of education is to provide an even starting point for kids regardless of their personal environment, it stands to reason that in places where those personal environments are worse you'd need brutal amounts of resources, since you'll indirectly be covering for parents' neglect, psychological issues, and other factors that should have been handled somewhere else but are being stuck in the education budget. If you see it under that scope, absolute numbers might not tell you much.
One kid has access to books and parents who read with them at home every night.
Another kid has no books at home and no learning support after they leave school.
How much is it going to cost to teach each child to read at the same proficiency level?
A school can only do so much to offset the negative impacts of poor home-life. Learned helplessness is real and debilitating and it is often learned at home at a young age. I empathize with the tax payers in this area who see above-average taxes for below-average results.
That's a genuinely curious question. I haven't researched any specifics about those schools or how they use their money.
It's possible for a vicious cycle to develop between waste/corruption in a school system and poor academic performance, wherein additional money doesn't help improve outcomes. That doesn't mean that withholding resources is the solution; rather, it means that a more fundamental restructuring than American municipal governments may be comfortable with is in order.