Easy to say, but it is hard to reverse. Those currently in cities don't have kids (yet?), and thus aren't interested in fixing the problems. Either they don't care at all, or they care more about who will keep the taxes low (since taxes translate into rent). For those that will eventually have kids this is to their detriment, but for the others.

Confounding this is the fact that those who do send their kids to city schools are poor because of lack of education and they are passing their lack of value for education to their kids. Even if one person does stay in the city it will be hard for their kids when all the peer pressure doesn't value education (this isn't insurmountable, but it is a negative parents have to fight)

Remember in the US schools have a significant amount of local control. The federal or state government in large part cannot step in and say "do thing this way" - even if we agreed on what is the right thing to do (we don't) the power to get anything done is lacking where it is needed.

In short there are significant headwinds that you would have to counter. You alone cannot do it, and getting enough other people interested is hard.