I'm not sure how to square that with the very well-studied result that areas with higher income tend to have better schools. Students from lower income brackets also do better than their income peers at schools in less affluent areas. And because local property taxes are a major funding source for schools, those are also the schools I'd expect to spend more because they have more.
Michigan notably does not fund schools through homeowner property taxes. I suspect that's probably the difference here and a reason we shouldn't use it as a representative example.
> And because local property taxes are a major funding source for schools, those are also the schools I'd expect to spend more because they have more.
It depends on the state. In Texas, property taxes from wealthier districts are redirected to poorer districts to ensure more equitable funding (search for "texas robin hood").
The result is that most public schools are funded about the same regardless of where they're located.
Could it be that people with higher incomes are a lot more likely to actually care about their kids getting a good education, and to put pressure on the school to that effect?