EDIT: the_gastropod's comment also under this parent is a great short summary of this issue. I second their recommendation of "Capital in the 21st Century"
That's about 1.1% of the net worth of Jeff Bezos.
I indicate this not to imply that Jeff Bezos should be solely responsible for fixing the Flint water supply, but rather to indicate that the resources are there, the problems are there, and what we lack is the will to move resources to fix public problems (be that via taxation or charity). Even problems we know will carry a larger cost moving forward... Flint is a town with a population of nearly 100,000, and a high-lead environment can basically guarantee higher costs in education, health problem remediation, and possibly crime.